Instead of looking for (a-b)^2 = 3 - 2 sqrt(2), I looked for (a + b sqrt(2))^2 = (3 - 2 sqrt(2)), with a, b rational numbers. The advantage here is that I don't have to pull a and b out of thin air: I can solve for them. In this case we have a^2 + 2 b^2 = 3 and 2ab = -2. There are two solutions here: a = -1, b = 1, and a = 1, b = -1. The latter choice is the positive result implied by the radical. So the answer is -1 + sqrt(2). How did I know to look for an answer in this form? From more advanced math, I know that Q[sqrt(2)] is a field, which means specifically for us that it's closed under multiplication. So it's a good place to start when looking for roots of a polynomial.
You can also use the fact that for a = sqrt(3 - sqrt(8)) and b = sqrt(3 + sqrt(8)) we find that ab = 1 and a + b = sqrt(8), hence x^2 - sqrt(8)x + 1 = 0 have - 1 + sqrt(2) and 1 + sqrt(2) for solution.
@@killanxv If (1) the coefficient in front of the second term is 2, and (2) the numbers summing to the first term are the same as factors multiplying to the radicand in the second term, then the answer is the sum or difference of the roots of the two numbers summing to the first term. See my post above. Gotta have that coefficient of 2 in front of the radical sign in the second term. √(15 + √200)) √200 = √(4 x 50) = 2√50. Bingo! Got the coefficient of 2. Now 10 + 5 = 15 and 10 x 5 = 50. Throw radical signs over 10 and 5 for your answer: √10 + √5. Note that we keep the sign in the original problem. Hope this helps.
Well we are not going to find it until we get fair question remember differential problem in 2021? İ dont know if youre university preparing student or you did but just check it out
A japanese guy once told me something that changed my life. He said that the common people's mind makes a very assertive division between leisure and studies. The secret is to look at exercises like puzzles or games, in such a way that you don't see youself as studing, but having fun instead. That's why nerds never get tired of studies, they can't stop indeed. I know its sounds crazy, but beleive me, it works very well, mainly im mathematics.
When I went to a secondary modern senior school in 1958 I was taught to be literate and numerate, I worked as a precision engineer but I don't have a clue what the lady is talking about.
People saying this is too simple, and while it kind of is simple, it is also hard to come up with unless you are trained to apply this kind of thinking in problems. I would have never guessed to use the square of difference identity, feels like its a problem you have to be familiar with beforehand
It's simple school book question in india probably from 8 or 9th grade it's just basic...😂 I didn't expect anything form American but atleast European can do it🤡😂...I guess now a days they are busy in teaching children about gender equality and lgbt😂🤡
"it is also hard to come up with unless you are trained to apply this kind of thinking in problems" . those who are spesicically trained for olympiands, will be trained for this and much more , becomes it too easy for them.
People commenting it is too simple are unrecognized genius. I wonder why they are wasting their time watching youtube videos. I mean, it is not the hardest question, but it does takes more thinking than a regular polynomial question and corresponds to high school students level
@@antronx7 I understand what you are trying to say but its a rule of mathematics that in Real numbers, √x is always non negative. What you mean to say is- Roots of X² are ±√(x²) See, the ± comes before a square root thing. This is because a square root can never be negative. In your case, X² = 9 X = ±√9 X = +3, -3
Now √(√9 - √8) = √(3 - 2√2). Now suppose √(√3 - 2√2) = a + b√2, where a and b are integers. This maybe not actually have a solution in integers, but if it does, we can find them as follows. Let 3 - 2√2 = (a + b√2)² = (a² + 2b²) + 2ab√2 So, 3 = a² + 2b² and -2 = 2ab So, (a = 1 and b = -1) or (a = -1 and b = 1). However, a + b√2 ≥ 0, as otherwise √(√9 - √8) would be a complex number, so we are forced to conclude that a = -1 and b = 1 is the only possible solution. So, √(√9 - √8) = -1 + 1*√2 = √2 - 1.
I'd start by relaxing to let a, b be rational numbers. Then be pleasantly surprised when they turn out to be integers. The rest of the process is exactly the same.
China and Romania have always been at the top when in comes to math, but I don't necessarily think the method used to achieve that goal was a positive one.
Appreciate that there are some Maths Olympiad questions within our grasp. I forgot the sqrt(square) trick from high school, but would have been able to do it then. These are like IIT JEE questions, maybe training questions, those students would argue. I expect IIT JEE students (even students) to call this easy by IIT JEE standard. Which would make me average in Maths. At 90 percentile in Quantitative Ability in the Stamford-Binet V test.
To solve the given expression, we can simplify it step by step: Simplify the square root of 9: v9=3 Simplify the square root of 8: v8=2v2 Substitute the simplified values back into the original expression: v3-2v2 Therefore, the solution to the given expression is v3-2v2
There is a rule if it is in the form of sqrt(sqrt(x+y)-2sqrt(x.y)) then the result is sqrt(x)-sqrt(y). For this question sqrt(sqrt(2+1)-2[sqrt(2)*sqrt(1)])=sqrt(2)-sqrt(1)=sqrt(2)-1
Well it's better to be said identity, since it holds for all Reals. Like a process has a rule to (for example) integrate by parts, you assume 1 function to be 1st and other to be second then you apply the formula of rule. Just my take.
This doesn't look exactly right. Square your RHS. You get (x + y) - 2 sqrt(xy). You need to lose one "sqrt" on the left hand side. To wit: sqrt((x + y) - 2 sqrt(xy)) = +/- (sqrt(x) - sqrt(y)), with the sign chosen on the RHS to ensure the number is positive.
Sadly I was totally confused. She showed us a rather lengthy process, but with ABSOLUTELY NO explanation for why we are doing all these arcane steps. I think this is probably the worst possible explanation of how to achieve the objective, because she showed us WHAT to do but with no explanation at all of WHY.
I would say that's not her fault but more the fault of mathematics. There is no rule or formula to ever tell you what to do next. In mathematics the only good answer to why did you do this is "because it works"
Sometimes I ask my self what is the benefit of such math, it is like guessing not a direct math , useless in normal job life , don’t expect nowadays mobile / comp. generation children need such bla bla
@@somgesomgedus9313 Actually I must respectfully disagree. To suggest that "because it works" is the only explanation needed in maths encourages rote learning, instead of gaining a true understanding of what you are doing, and why. Mathematics is a language used for the manipulation of symbols: "because it works" is like learning the words of a spoken language without learning their meaning. It renders you helpless when faced with a novel situation, and that is not how we should teach maths.
This method is called compleating the square. You map your current problem on the binomial formula and then use it to simplify the problem. Which she did. I did not watch the video with sound on. Not sure why everyone is so negative in the comments...
It's simple school book question in india probably from 8 or 9th grade it's just basic...😂 I didn't expect anything form American but atleast European can do it🤡😂...I guess now a days they are busy in teaching children about gender equality and lgbt😂🤡
Solved by AI √9-√8=? To evaluate the expression √9 - √8, we need to simplify the square roots. √9 = √(3²) = 3 (since 3² = 9) √8 = √(2² × 2) = 2√2 (since 2² × 2 = 8) Now, subtract: 3 - 2√2 To simplify further, we can approximate 2√2 as 2.83. 3 - 2.83 = 0.17 So, √9 - √8 ≈ 0.17.
I do not know how much time it would take for me until realizing that 3 - 2sqrt(2) can be easily presented in a form of a^2 - 2ab + b^2. Do mathematicians have a special ability to glance it on the spot when something can be recombined according to the known rule?
I think it is more about having experience and mastery with those tools. In many schools we skip to differentials and integrals before having a solid grasp on foundations of math. It's like they think mathematics was an intellectual desert up until newton and Leibniz. If students are educated to maximize their mathematical tools before learning new ones, they'd know how to solve these problems. (The Israeli school system is worse than the american, we don't even learn completing the square, so we'd have no intuition for solving this kind of problem)
@@TheMeiravital Thank God they did do that otherwise I would have failed math. Memorizing patterns is not as useful as understanding why. ESPECIALLY once you realize that in the real world math never works out nicely like that.
I thought I was the only one who had this shitty problem, I had to solve advanced math problems without having enough time to fully memorize algebra formulas due to lockdown. And now everyone is kicking ass
I think they just saw the same or very similar solutions over and over. I asked my math professor a question before and he solved it by adding 1 to the both sides of the equation. When I asked why would he do something weird like that and he told me that they just get used to this patterns over the years.
Can somebody help me with this question: task: Arthur and Renate are playing on a square game board divided into 7 x 7 squares. Arthur has two red stones initially placed in the bottom left and top right corner squares, while Renate has two black stones initially placed in the top left and bottom right corner squares. On their turn, a player selects one of their two stones and moves it to a horizontally or vertically adjacent free square. Arthur and Renate take turns, with Arthur starting. Arthur wins if, after a finite number of moves, his two stones are in horizontally or vertically adjacent squares. Can Renate prevent this by making clever moves?
Esatto. Dai che a novembre quando non sarò più quello dei numeri e tiferò Putin che farà un bel botto nucleare vi regalerò giubbotti di plastica a specchio, piscine in muratura e motomacchine che sfrecciano a 500 orari. Da novembre ci divertiamo tutti contro tutti col finale nucleare planetario
To simple 🙃 √( √9 - √8) √( 3 - √8) √( 3 - 2×1.41) √( 3 - 2.82) √( .18 ) => near to √16 So as my own formula 😂 ( work only when number are near to root ) Information √.16=> .4 √.18 .4 + 1/18 => .4 + .056 => .456 (it is approx without so much calculations 😅) Well the 1/18 , its come from my formula Like if someone root value are near to square √24 = √25 - (25-24)/( *2* * 25) *2* is constant 😊
Instead of doing this simply let the whole thing be x and form a quadritic equation and just solve it. Isn't it better to give all the possible values rather than just 1 value?
I know the trick too.... But if anybody don't know the trick of solving it directly....they too have to give a minute..... Professor of college who are doing PhD in mathematics don't know such trick and they may take a minute to solve it's doesn't mean that they know less math than you okay...... I hope you otherstand the difference
@@mathematicsman7454 I am not judging anyone as If someone is able to solve this problem she may be genius and the one who isn't is weak in maths . I was just saying that even in Maths Olympiad , there comes questions which can be solved just by basics ! Well I respect your opinion ..
I'm asking because I'm really curious. When do foreign countries learn this kind of math? Korea is mastered at 16-17 years old. After 3 days of learning, we go straight to the more difficult stage.
To solve the problem here, two symbols used ie. "Is equal to" and "implies". For simplification "is equal to" is used. But to solve an equation "implies" symble is used.
do you all Know that math olympics have some simple questions here and there to slow participants down and reward faster solutions right? This Its ONE example of such questions. You solve it quickly to have more time to solve the actual problems Good luck with the other questions "genius"
It's simple school book question in india probably from 8 or 9th grade it's just basic...😂 I didn't expect anything form American but atleast European can do it🤡😂...I guess now a days they are busy in teaching children about gender equality and lgbt😂🤡
@@eliasbram3710math olympiad problems usually have a trick to them that isn’t commonly known, that’s why they are so hard. this however, is a textbook example of denesting square roots most people interested enough in contest math algebra would know. unfortunately, it is clickbait. this is not a MO level problem
Equation with double radical The first number will be added to the second. And then it's going to be the product of the first number and the second. ✓3-2√2= S=2+1=3. P=2.(-1)=-2. ✓2-1 .
In1990ies in ist. muhendislik one of our friend proved a wellkown physics equation's incorrectnessby maths but these kids are smiling on you ,dont worry you're in the right path...
I am a student Can you tell me what I did wrong trying to solve this √((√9)-(√8))= x √9-√8=x² 9-2×√9×√8+8=x⁴ 9-2×3×2√2+8=x⁴ 17-12√2=x⁴ x=fourth root of 17-12√2 But the answer I'm getting is 0.4142135..... Which is also the same answer I'm getting for √(√9-√8). (0.4142135.....) Edit: I'm an idiot I thought you said the answer is sqrt of 2, didn't hear the part where you said sqrt of 2 -1, that makes a lot more sense. So my answer is correct.
I can do it shortly as to remove the whole square root and give power on both and cancel the square in to second rood know we get 9-8 and ans would be 1
Funny i always thought algebra was magical until i learned trigonometry. Then i was amazed on how it is used in daily life. I always questioned when i would need to use algebra in daily tasks... 😅
I always see Indians in comment section only to brag about themselves. Usually this means a lack of confidence and self-respect. Is India one of the leaders in technology in the world?
Simpler n Shorter Solution : 3 - 2 x Sq Rt of 2 = Z x Z OR Square of Z = 3 - ( 2 x 1.41 ) = 3 - 2.82 Therefore Sqr of Z = 0. 18 So Z = Sq Rt of 0. 18 Answer = 0. 424
Don't make it complicated Sqrt(√9-√8) = sqrt(3-2√2) (If you think about it 3=1²+√2² also 2√2 is 2*1*√2 so it matches with (a+b)² = a²+b²+2ab ) So, Sqrt(3-2√2) = sqrt(1²+2√2²-2√2) =Sqrt((1-√2)²) =1-√2 Of it can also be √2-1 because of sqrts
Thank you girl, from the buttom of my heart. I nearly end up in the asylum trying to solve exercises like this. Besides a great mathematician you also have psyquiatric talents.
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My friends please don't crack your heads. Here the teacher should have said that this works as Quad Eq with 3 and a number inside radical i.e 2 so 2+1=3 and 2x1=2 so a=2 and b=1
In everyday life no, but the general take away from problems like this is exercising the notion of manipulating mathematical expressions into different forms to make them simpler (i.e., easier to manage, interpret, etc). This particular example isn't that complicated, but the general skill of simplification can come in handy in certain jobs. Like if one were to come up with a certain formula to describe a particular phenomena that's unique to that company, someone else may want to manipulate the form of that formula so to make its terms more explicit.
I have a backlog in math, so not a qualified person to address this, but any question is hard if you don't know the method to solve it. You know this already, sweetheart...❤
@@andrewsies9065for a **real** non-negative integer like the 2? A square root of is an irrational number. If it were -2, I would agree that imaginary part of the number exists.
@@andrewsies9065 No, there are two roots to the polynomial x^2 - 4 = 0. Only one of those two is the "square root," the positive one. "square root" is a well-defined function whose range is the non-negative real numbers. It's not ambiguous about which of the two roots it refers to.
√(√9 - √8) = √(3 - 2√2) = √(3 - 2(1.414)) = √(3 - 2.828) = √0.172 Using square root formula to derive the sq.root of 0.172 = | 0.172 | like this We get, 0.414 the answer THIS IS HOW I DID IT.
I was able to answer in first glance it it has roughly taken me a 30-35 seconds.. If you have already practised this type of questions then this wont really take time you can by a shortcut also that you should know if you are in 9th or above
It is too simple for Math-Olympiad.
Agreed
No
@@furina9053Olympiad math is just a whole different level man, thats why they mentioned it
I think it was maybe paralympic games
Maybe it was from the qualifier level exam
Instead of looking for (a-b)^2 = 3 - 2 sqrt(2), I looked for (a + b sqrt(2))^2 = (3 - 2 sqrt(2)), with a, b rational numbers. The advantage here is that I don't have to pull a and b out of thin air: I can solve for them.
In this case we have a^2 + 2 b^2 = 3 and 2ab = -2. There are two solutions here: a = -1, b = 1, and a = 1, b = -1. The latter choice is the positive result implied by the radical. So the answer is -1 + sqrt(2).
How did I know to look for an answer in this form? From more advanced math, I know that Q[sqrt(2)] is a field, which means specifically for us that it's closed under multiplication. So it's a good place to start when looking for roots of a polynomial.
Lies again? Must See TV Deaf Blind
I remember seeing this trick of manipulation of sqrt(2) like imaginary numbers, but I didn’t realize it had a formal name Q(sqrt(2))
You can also use the fact that for a = sqrt(3 - sqrt(8)) and b = sqrt(3 + sqrt(8)) we find that ab = 1 and a + b = sqrt(8), hence x^2 - sqrt(8)x + 1 = 0 have - 1 + sqrt(2) and 1 + sqrt(2) for solution.
So -1 is on of your answers for a square root problem? What times what equals negative 1?
Ooops...
2+2= 4
One should be careful in distinguishing between 'equals' and 'implies' symbols.
=(√3-2√2)^2
=3-2√2//
√(3 - 2√2). Shortcut: 2 + 1 = 3 and 2 x 1 = 2. Automatic: √2 - √1 which simplifies to √2 - 1. Use the shortcut and don't overthink it.
i didn't get your point
@@killanxv If (1) the coefficient in front of the second term is 2, and (2) the numbers summing to the first term are the same as factors multiplying to the radicand in the second term, then the answer is the sum or difference of the roots of the two numbers summing to the first term. See my post above. Gotta have that coefficient of 2 in front of the radical sign in the second term. √(15 + √200)) √200 = √(4 x 50) = 2√50. Bingo! Got the coefficient of 2. Now 10 + 5 = 15 and 10 x 5 = 50. Throw radical signs over 10 and 5 for your answer: √10 + √5. Note that we keep the sign in the original problem. Hope this helps.
@@jim2376made even more difficult 😂 , what is a radicand ? Too simple earlier , it happens by simple instincts
@@abhishekchhikara4100That's for people like you, just go and read definitions and you can see the word radicand is so common in most textbooks
What happens when your teacher wants to see the problem worked step by step?
I hope one day everyone finds the peace in math! Love from Türkiye.
Well we are not going to find it until we get fair question remember differential problem in 2021? İ dont know if youre university preparing student or you did but just check it out
A japanese guy once told me something that changed my life. He said that the common people's mind makes a very assertive division between leisure and studies. The secret is to look at exercises like puzzles or games, in such a way that you don't see youself as studing, but having fun instead. That's why nerds never get tired of studies, they can't stop indeed. I know its sounds crazy, but beleive me, it works very well, mainly im mathematics.
When I went to a secondary modern senior school in 1958 I was taught to be literate and numerate, I worked as a precision engineer but I don't have a clue what the lady is talking about.
Bro this for real made me fall of my bed laughin
She got this "trick" out of a Deus Ex Machina
People saying this is too simple, and while it kind of is simple, it is also hard to come up with unless you are trained to apply this kind of thinking in problems. I would have never guessed to use the square of difference identity, feels like its a problem you have to be familiar with beforehand
Yupp, one must have known the patterns before
I think its not that hard. In √(3-2√2), the 3-2√2 is inside a sq root, which makes us try forms like (a±b)^2
It's simple school book question in india probably from 8 or 9th grade it's just basic...😂 I didn't expect anything form American but atleast European can do it🤡😂...I guess now a days they are busy in teaching children about gender equality and lgbt😂🤡
"it is also hard to come up with unless you are trained to apply this kind of thinking in problems"
.
those who are spesicically trained for olympiands, will be trained for this and much more , becomes it too easy for them.
@mar2506 an averag 8th grader from India will be able to this in seconds brh.
U'll find this in cbse books
People commenting it is too simple are unrecognized genius. I wonder why they are wasting their time watching youtube videos. I mean, it is not the hardest question, but it does takes more thinking than a regular polynomial question and corresponds to high school students level
Skill issue 😂
Ha ha
So funny man.
You probably should become a standing comedian@@dhonikumarshahi2806
Is it high school level?😂 not 8th grade?
Im not a genius and I solved it in my head lying in bed in about 60 seconds. It's too simple
@@archmaneric9251 sarcasm
I am a genuine maths dunce. Don't remember learning any of this and I don't understand it now either! 😅
Every one has their own unique talent sir....
Bro are you from America 😂
@@Ispeakwithlogicif you think Americans are dumb you should see which country has the most medals in International Math Olympiad
Nice trick
Its not for genius it's for children .
Because in the main question the number under square root is definitely positive, as squared root of 9 is bigger than squared root of 8.
Then again, the square root of 9 is also -3, so there are two answers.
@@scottrichmond3548 square root of 9 is 3 not -3
@@rudraroopbhattacharjee6191 what's -3 * -3 ?
@@antronx7 9
@@antronx7 I understand what you are trying to say but its a rule of mathematics that in Real numbers, √x is always non negative.
What you mean to say is-
Roots of X² are ±√(x²)
See, the ± comes before a square root thing. This is because a square root can never be negative.
In your case,
X² = 9
X = ±√9
X = +3, -3
Now √(√9 - √8) = √(3 - 2√2).
Now suppose √(√3 - 2√2) = a + b√2, where a and b are integers. This maybe not actually have a solution in integers, but if it does, we can find them as follows.
Let 3 - 2√2 = (a + b√2)²
= (a² + 2b²) + 2ab√2
So, 3 = a² + 2b² and -2 = 2ab
So, (a = 1 and b = -1) or (a = -1 and b = 1).
However, a + b√2 ≥ 0, as otherwise √(√9 - √8) would be a complex number, so we are forced to conclude that a = -1 and b = 1 is the only possible solution.
So, √(√9 - √8) = -1 + 1*√2 = √2 - 1.
It can be the other method which is great but the standard one is more easy and convinnient
I'd start by relaxing to let a, b be rational numbers. Then be pleasantly surprised when they turn out to be integers. The rest of the process is exactly the same.
We were solving such problems in my 8th grade in Romania in a regular maths class. Too simple for an Olympiad.
no one cares
I'm sure third world Romania isn't.
I wonder if no baddy needs mathema😊ticks why still teach them
Cope and seethe.
China and Romania have always been at the top when in comes to math, but I don't necessarily think the method used to achieve that goal was a positive one.
Appreciate that there are some Maths Olympiad questions within our grasp.
I forgot the sqrt(square) trick from high school, but would have been able to do it then.
These are like IIT JEE questions, maybe training questions, those students would argue.
I expect IIT JEE students (even students) to call this easy by IIT JEE standard.
Which would make me average in Maths. At 90 percentile in Quantitative Ability in the Stamford-Binet V test.
yeah, it's an easy question. Like JEE Mains level probably.
@@eddie31415 this is class 9 school level.
This question is in Class 9 R D Sharma Factorisation of Polynomials fill in the blanks in the form of √3 -2√2.
@@eddie31415 lol no 8th or 9th class problem maybe jee mains level are far more harder than thiss
@@eddie31415 it's a grade 9th or 10th question maybe
As a martian, I teached myself this trick at 6 months old, by observing shadow patterns in our red planet.
😂
Ain't no martian looks like a mongoose 🗣️
Don't let Elon Musk colonize Mars. What a pity if the red planet becoming stupid as Earth.
To solve the given expression, we can simplify it step by step:
Simplify the square root of 9: v9=3
Simplify the square root of 8: v8=2v2
Substitute the simplified values back into the original expression: v3-2v2
Therefore, the solution to the given expression is v3-2v2
Why do you need ( a-b)(a-b)? You can simply find the answer at 3-2√2 only na. 3-2*1.414=3-2.828=.172=√.172=.414 which is the same one.
Im guessing you're not allowed a calculator in this exam , as such your calculation are only approximation and can't be used as answers.
@@lesouni9342 you don't need a calculator for such easy things.you don't even need a pen& paper for sure.
2+8= 10
Hiding qusoin are
There is a rule if it is in the form of sqrt(sqrt(x+y)-2sqrt(x.y)) then the result is sqrt(x)-sqrt(y). For this question sqrt(sqrt(2+1)-2[sqrt(2)*sqrt(1)])=sqrt(2)-sqrt(1)=sqrt(2)-1
Well it's better to be said identity, since it holds for all Reals. Like a process has a rule to (for example) integrate by parts, you assume 1 function to be 1st and other to be second then you apply the formula of rule. Just my take.
This doesn't look exactly right. Square your RHS. You get (x + y) - 2 sqrt(xy). You need to lose one "sqrt" on the left hand side. To wit: sqrt((x + y) - 2 sqrt(xy)) = +/- (sqrt(x) - sqrt(y)), with the sign chosen on the RHS to ensure the number is positive.
Sadly I was totally confused. She showed us a rather lengthy process, but with ABSOLUTELY NO explanation for why we are doing all these arcane steps. I think this is probably the worst possible explanation of how to achieve the objective, because she showed us WHAT to do but with no explanation at all of WHY.
Actually a lot of Math teachers I met explain things in this way, which can be rather frustrating
What do you expect from an Asian?
I would say that's not her fault but more the fault of mathematics. There is no rule or formula to ever tell you what to do next. In mathematics the only good answer to why did you do this is "because it works"
Sometimes I ask my self what is the benefit of such math, it is like guessing not a direct math , useless in normal job life , don’t expect nowadays mobile / comp. generation children need such bla bla
@@somgesomgedus9313 Actually I must respectfully disagree. To suggest that "because it works" is the only explanation needed in maths encourages rote learning, instead of gaining a true understanding of what you are doing, and why. Mathematics is a language used for the manipulation of symbols: "because it works" is like learning the words of a spoken language without learning their meaning. It renders you helpless when faced with a novel situation, and that is not how we should teach maths.
Nicely done and thank you.
However, I'll just use my handy electronic calculator for these kind of problems.
Real Olympiad questions
Let a and b be positive integers such that ab+1 divides a²+b². Show that a²+b²/ab+1 is the square of an integer.
What's the motivation for trying to express it as a^2 - 2ab + b^2? If you don't already know the answer, why would you do that?
This method is called compleating the square. You map your current problem on the binomial formula and then use it to simplify the problem. Which she did.
I did not watch the video with sound on. Not sure why everyone is so negative in the comments...
It's simple school book question in india probably from 8 or 9th grade it's just basic...😂 I didn't expect anything form American but atleast European can do it🤡😂...I guess now a days they are busy in teaching children about gender equality and lgbt😂🤡
Solved by AI
√9-√8=?
To evaluate the expression √9 - √8, we need to simplify the square roots.
√9 = √(3²) = 3 (since 3² = 9)
√8 = √(2² × 2) = 2√2 (since 2² × 2 = 8)
Now, subtract:
3 - 2√2
To simplify further, we can approximate 2√2 as 2.83.
3 - 2.83 = 0.17
So, √9 - √8 ≈ 0.17.
I do not know how much time it would take for me until realizing that 3 - 2sqrt(2) can be easily presented in a form of a^2 - 2ab + b^2. Do mathematicians have a special ability to glance it on the spot when something can be recombined according to the known rule?
I think it is more about having experience and mastery with those tools. In many schools we skip to differentials and integrals before having a solid grasp on foundations of math. It's like they think mathematics was an intellectual desert up until newton and Leibniz. If students are educated to maximize their mathematical tools before learning new ones, they'd know how to solve these problems. (The Israeli school system is worse than the american, we don't even learn completing the square, so we'd have no intuition for solving this kind of problem)
@@TheMeiravital😂
@@TheMeiravital Thank God they did do that otherwise I would have failed math. Memorizing patterns is not as useful as understanding why. ESPECIALLY once you realize that in the real world math never works out nicely like that.
I thought I was the only one who had this shitty problem, I had to solve advanced math problems without having enough time to fully memorize algebra formulas due to lockdown. And now everyone is kicking ass
I think they just saw the same or very similar solutions over and over. I asked my math professor a question before and he solved it by adding 1 to the both sides of the equation. When I asked why would he do something weird like that and he told me that they just get used to this patterns over the years.
Can somebody help me with this question:
task:
Arthur and Renate are playing on a square game board divided into 7 x 7 squares. Arthur has two red stones initially placed in the bottom left and top right corner squares, while Renate has two black stones initially placed in the top left and bottom right corner squares. On their turn, a player selects one of their two stones and moves it to a horizontally or vertically adjacent free square. Arthur and Renate take turns, with Arthur starting. Arthur wins if, after a finite number of moves, his two stones are in horizontally or vertically adjacent squares. Can Renate prevent this by making clever moves?
Para los que piden solución negativa, recuerden que:
x^2=4
no es lo mismo que
x=√4
....
Esatto. Dai che a novembre quando non sarò più quello dei numeri e tiferò Putin che farà un bel botto nucleare vi regalerò giubbotti di plastica a specchio, piscine in muratura e motomacchine che sfrecciano a 500 orari. Da novembre ci divertiamo tutti contro tutti col finale nucleare planetario
pero cuadrados negatvos no existen
2+2 =4
4+4 = 8
To simple 🙃
√( √9 - √8)
√( 3 - √8)
√( 3 - 2×1.41)
√( 3 - 2.82)
√( .18 ) => near to √16
So as my own formula 😂 ( work only when number are near to root )
Information √.16=> .4
√.18
.4 + 1/18
=> .4 + .056
=> .456 (it is approx without so much calculations 😅)
Well the 1/18 , its come from my formula
Like if someone root value are near to square
√24 = √25 - (25-24)/( *2* * 25)
*2* is constant 😊
What kind of pen are you using? I’ve been looking for a fine-point pen for ages!
I'm glad someone else asked this question.
Since Sq root of 2 -1 is positive you don't have to use absolute value
I knew this ...i just forget about it. That's what happens when you don't stay in practice
Ashole cleaning in Hospital useless.
Instead of doing this simply let the whole thing be x and form a quadritic equation and just solve it. Isn't it better to give all the possible values rather than just 1 value?
Being an IIT - JEE aspirant from India , It is one of the easiest category of maths problem I ever met !
I know the trick too.... But if anybody don't know the trick of solving it directly....they too have to give a minute..... Professor of college who are doing PhD in mathematics don't know such trick and they may take a minute to solve it's doesn't mean that they know less math than you okay...... I hope you otherstand the difference
@@mathematicsman7454 I am not judging anyone as If someone is able to solve this problem she may be genius and the one who isn't is weak in maths . I was just saying that even in Maths Olympiad , there comes questions which can be solved just by basics ! Well I respect your opinion ..
Thankyou for being my competition
And in IIT JEE we never got such questions
@@deepamurthy198 Yah !
I'm asking because I'm really curious.
When do foreign countries learn this kind of math?
Korea is mastered at 16-17 years old.
After 3 days of learning, we go straight to the more difficult stage.
√{a ± b√c} (a,b,c non-neg. rat.) can be simplified to √y±√z iff {a² - b².c} = d².
If this d exists, then take y = (a+d)/2 & z = (a-d)/2. Here a=3, b=2, & c=2.
So d = √{3² - 2².2} = √{9 - 8} = √1 = 1. So y = {3+1}/2 = 2 & z = {3-1}/2 = 1.
Hence √{√9 - √8} = √{3 - 2√2} = √y - √z = √2 - √1 = (√2) - 1.
What does the last instruction read. Is it English? I couldn't decipher.
2+2=4
3_2 1
2_ 0
2_ 1 0
It's simple
Question for Vedic Mathematics
=√3-2.8286
=√0.1714
*=0.414*
I am totally lost from the start.
Please give any practical use of learning this?
To solve the problem here, two symbols used ie. "Is equal to" and "implies". For simplification "is equal to" is used. But to solve an equation "implies" symble is used.
Can you specify the implies symbol?
This is a standard problem. You reduce it to sqrt (sqrt (9)+sqrt(8))=sqrt (2+2\sqrt(2)+1)=sqrt(2)+1.
it's for secondary school in Vietnam 😂
True story 😂
I suck at maths, but found this very calming. Please advise using the problem above, where would I use it in life? Many thanks....
I could have gone my whole life without knowing that answer! Now I know!
Please help me to solve using diff of 2 sq as mentioned by teacher but not followed.
√(√9+√8) =√(3+√8) = √x + √y
Then,
x+y =3
x-y=1 √2 + √1
*Get it from Carr's synopsis ( book used by ramanujan to self study)
3+3=6
3+3= 6
Interesante y didáctica explicación, muchas gracias por compartir 😊❤😊
I never used the (a±b)² formula like that before, thats brilliant
2+2= 4
Used calculator, got same result.💪
Work smarter not harder 💪
2V2=2ab =2×1×V2>>1×V2 (a=1 ,b=V2 or a=V2 ,b=1)
If this is a math-olympiad question, I'm a genius
do you all Know that math olympics have some simple questions here and there to slow participants down and reward faster solutions right?
This Its ONE example of such questions. You solve it quickly to have more time to solve the actual problems
Good luck with the other questions "genius"
This shows a technique, it is kept simple to make the point come across more easily. In a real question, this could be one step in the middle.
you're right: its not a math olympiad question. Clickbait
It's simple school book question in india probably from 8 or 9th grade it's just basic...😂 I didn't expect anything form American but atleast European can do it🤡😂...I guess now a days they are busy in teaching children about gender equality and lgbt😂🤡
@@eliasbram3710math olympiad problems usually have a trick to them that isn’t commonly known, that’s why they are so hard. this however, is a textbook example of denesting square roots most people interested enough in contest math algebra would know. unfortunately, it is clickbait. this is not a MO level problem
A lot of work while there is simpler shot cut . Where did a and b come from
Why does the final answer have to be positive?
the root of x square = module x(module≥0)
@@flam1ex186 a square root can be both positive and negative
@@sureshmukhi2316 that is true for complex numbers/functions. For reals it must be positive.
Root doesn't contain negative
If a root can't be negative then explain the quadratic formula?
Equation with double radical The first number will be added to the second. And then it's going to be the product of the first number and the second.
✓3-2√2= S=2+1=3. P=2.(-1)=-2. ✓2-1 .
3_2 1
As a Turkish student who studied for university entrance exam, I am really sad that I solved this question like in seconds from my mind.
So which University did you end up 😬 😁
@@SunriseLAWroasted
Funny how so many third world students come here to brag about being able to solve this.
@@egeozel80hes cleaning washrooms for a living
In1990ies in ist. muhendislik one of our friend proved a wellkown physics equation's incorrectnessby maths but these kids are smiling on you ,dont worry you're in the right path...
I am a student
Can you tell me what I did wrong trying to solve this
√((√9)-(√8))= x
√9-√8=x²
9-2×√9×√8+8=x⁴
9-2×3×2√2+8=x⁴
17-12√2=x⁴
x=fourth root of 17-12√2
But the answer I'm getting is 0.4142135.....
Which is also the same answer I'm getting for √(√9-√8). (0.4142135.....)
Edit: I'm an idiot I thought you said the answer is sqrt of 2, didn't hear the part where you said sqrt of 2 -1, that makes a lot more sense. So my answer is correct.
I love maths but the way she explains it its juicy way of explaining.
By the time she finished the square root I was SQUARE DANCING 😁
Your just doing the math there’s no explaination along the way.
You don't need the moduls, it's already known that radical 2 > radical 1
It would be interesting to see this used in an actually useful use case. My brain has a hard time following nonsensical “just because” problems
What do you define as an actual "useful use case"?
Find the roots of x^4-6x^2+1
@@lestath2345 tell me a real world instance where this would be used other than a math class
@@WoodrowWoods2007 In the field of pure math. Also, we're mostly doing this for the sake of doing it, just like playing video games, *for fun*.
@@lestath2345yes it is a brain exercise. Opens the horizons of brain
I can do it shortly as to remove the whole square root and give power on both and cancel the square in to second rood know we get 9-8 and ans would be 1
Funny i always thought algebra was magical until i learned trigonometry. Then i was amazed on how it is used in daily life. I always questioned when i would need to use algebra in daily tasks... 😅
I was always functionally retarted with maths. Could someone tell me the situation where such learning used in real life ?
As an Indian, I appeared this question at SOF Mathematics Olympaid in my third grade
I always see Indians in comment section only to brag about themselves. Usually this means a lack of confidence and self-respect. Is India one of the leaders in technology in the world?
Simpler n Shorter Solution :
3 - 2 x Sq Rt of 2 = Z x Z
OR
Square of Z =
3 - ( 2 x 1.41 )
= 3 - 2.82
Therefore
Sqr of Z = 0. 18
So Z = Sq Rt of 0. 18
Answer = 0. 424
Im very weak in math but somehow completed intermediate with 97% in math and completed my engineering a month ago 😂
No one asked
@@AdityaKumar-gv4dj No one answered you! Saala
3-2root2=(root2-1) square under root square and roof goes the answer is root2-1
Don't make it complicated
Sqrt(√9-√8) = sqrt(3-2√2)
(If you think about it 3=1²+√2² also 2√2 is 2*1*√2 so it matches with (a+b)² = a²+b²+2ab )
So,
Sqrt(3-2√2) = sqrt(1²+2√2²-2√2)
=Sqrt((1-√2)²)
=1-√2
Of it can also be √2-1 because of sqrts
I don't like abstract short cuts. Too complicated.
Why module of the solution in the end? The solution is already a number and also a positive one.
Please do not write sqrt(2)= 1,414 This was the moment when you lost me.
@@buddy0479 You are mistaken. In the UK it is also 1.414. It is other European countries such as France and Germany where this occurs.
I got the answer as soon as i saw it 😂 i remember 40 years ago my teacher still be asking for the pointless work lol
Where did you pull out the value of the square root of 2 from?
Why ? 😳🤷♂️
3-2✓2 = 3-2*1.414 just product and subtract will give your answer
Kinda useless for ANY practical purposes ...sqrt(sqrt(9) -sqrt(8)) is solved using a pocket calculator
Thank you girl, from the buttom of my heart. I nearly end up in the asylum trying to solve exercises like this. Besides a great mathematician you also have psyquiatric talents.
We have Ramanujan Technique to solve this in the mind itself.
As Indian I can confirm this we did in grade 6
Shortcut √3-2x1.4=0.447, just compare from the options
This will not come in SG math olympiad. they be testing quadratic formula and equations for junior.
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My friends please don't crack your heads. Here the teacher should have said that this works as Quad Eq with 3 and a number inside radical i.e 2 so 2+1=3 and 2x1=2 so a=2 and b=1
2×1=2
1+1=2
2+1=3
Very interesting, although in practice it is not needed for anything in life :)
In everyday life no, but the general take away from problems like this is exercising the notion of manipulating mathematical expressions into different forms to make them simpler (i.e., easier to manage, interpret, etc).
This particular example isn't that complicated, but the general skill of simplification can come in handy in certain jobs. Like if one were to come up with a certain formula to describe a particular phenomena that's unique to that company, someone else may want to manipulate the form of that formula so to make its terms more explicit.
@@Chrisratatabruh
Certainly you won’t need it don’t worry
It's just for improving your thinking skills.
You don't, but the smart people do
I am an Azerbaijan pupil. Question is very easy. I found the solution to the question as soon as I saw it
In Asia, a bad student in 2nd school can easily do this math :))
Root 2 - 1, solved in less than a second orally 😅, a better version of the problem always appears in school level maths olympiad so just used to it.
Очень легкая и известная задача
Средний вопрос олимпиады по математике в Юпитере
Ключевое слово "известная". Всё легко и просто, когда известно. Жаль, что до людей не доходит элементарная вещь
Why you use modulus?
This is actually really simple for an olympiad 😂
I have a backlog in math, so not a qualified person to address this, but any question is hard if you don't know the method to solve it. You know this already, sweetheart...❤
I fell asleep at 0:23.🥴
Shouldnt it be (√2)²- 2×√2×1 + (1)² ?? Coreect me if im wrong
Could someone explain why we would need the modulo when 2 and 1 are both greater or equal to zero and both are integers?
There are two values for a square root- a number and it’s additive inverse
@@andrewsies9065for a **real** non-negative integer like the 2? A square root of is an irrational number. If it were -2, I would agree that imaginary part of the number exists.
@@hochh6978 yes. For example there are two square roots of four: 2 and -2. The same applies for all positive integers even if they are irrational.
@@andrewsies9065 thank you!
@@andrewsies9065 No, there are two roots to the polynomial x^2 - 4 = 0. Only one of those two is the "square root," the positive one.
"square root" is a well-defined function whose range is the non-negative real numbers. It's not ambiguous about which of the two roots it refers to.
So why isn’t the answer .414? Why stop 1 step short like that?
Trick is in figuring out the algebraic identity applicable to the Olympiad question
√(√9 - √8)
= √(3 - 2√2)
= √(3 - 2(1.414))
= √(3 - 2.828)
= √0.172
Using square root formula to derive the sq.root of 0.172 = | 0.172 | like this
We get, 0.414 the answer
THIS IS HOW I DID IT.
can you solve stock market predication with previous value
Oh, that voice, that accent! ❤️
It's a nice problem and thanks for your video. Please however do not write "=>" when dealing with terms. It leads many students to improper notation.
Why not subtract under root of 8 from under root of 9
I was able to answer in first glance it it has roughly taken me a 30-35 seconds..
If you have already practised this type of questions then this wont really take time you can by a shortcut also that you should know if you are in 9th or above
Solve the following equation in IR :
Cos(1954x-1962)=Pi
🖍️🇩🇿🖍️🇩🇿🖍️
in this do we have to find the value of x?
@@anushreegoel6628no, Pi
Make it cos-¹ instead. This has no soln
@@prakhar77495 not no solution, man... This is just downright wrong lol. cos(theta) cannot have value higher than 1
@@iroveth6690 so did u get the value?
Is 2** 1/2 -1 a simpler form than 3 - 2*2**1/2? Not by much!