3 ways to "complete the square"

แชร์
ฝัง
  • เผยแพร่เมื่อ 1 ม.ค. 2025

ความคิดเห็น • 295

  • @blackpenredpen
    @blackpenredpen  3 ปีที่แล้ว +149

    Have you impressed your teachers (or students) yet???

    • @Ashmit_1729
      @Ashmit_1729 3 ปีที่แล้ว +6

      Yes by factoring 2

    • @davidbrisbane7206
      @davidbrisbane7206 3 ปีที่แล้ว +6

      Yes indeed. When I showed them how to use Wolfram Alpha to solve quatratic equations 😁.

    • @أميرالبلابل
      @أميرالبلابل 3 ปีที่แล้ว +2

      Yeah, when I correct my teacher hahahah

    • @invaderzim6842
      @invaderzim6842 3 ปีที่แล้ว +2

      Hi ,blackpenredpen!I really enjoy your content. I’ll very much appreciate if u can solve me this problem
      Find x for:2^((sin(x))^2014)-2^((cos(x))^2014)=(cos(2x))^2013
      I know it is a tough problem ,but I really want to know the way to solve this kind of problem 😅

    • @sbusisoquintin8004
      @sbusisoquintin8004 3 ปีที่แล้ว

      Not yet we are waiting for them😅💯
      Support from South Africa🇿🇦

  • @shaurya1616
    @shaurya1616 3 ปีที่แล้ว +398

    I think his immense knowledge comes from the pokeball.

    • @yensteel
      @yensteel 3 ปีที่แล้ว +4

      Agreed

    • @mama5402
      @mama5402 3 ปีที่แล้ว +6

      I guess that's why he looks like a pokemon xd...

    • @arjunsahu2543
      @arjunsahu2543 3 ปีที่แล้ว +2

      😂🤣🤣

    • @williamsmamanimamani846
      @williamsmamanimamani846 3 ปีที่แล้ว +1

      Estoy totalmente de acuerdo, mi estimado

    • @xxmysticexpertxx113
      @xxmysticexpertxx113 3 ปีที่แล้ว +6

      Pikachu tellin him the answers

  • @SyberMath
    @SyberMath 3 ปีที่แล้ว +49

    You have a way with Complex Numbers! Nice work!!! 🤩

    • @blackpenredpen
      @blackpenredpen  3 ปีที่แล้ว +5

      Thanks! 😃

    • @SyberMath
      @SyberMath 3 ปีที่แล้ว +4

      @@blackpenredpen My pleasure! 😊

    • @vivekbhutada3049
      @vivekbhutada3049 3 ปีที่แล้ว

      Hey syber! Big fan here!!

    • @erikmensinga
      @erikmensinga 3 ปีที่แล้ว

      @marine dtadtfeld bruh no why

  • @justacityboy4426
    @justacityboy4426 3 ปีที่แล้ว +188

    Math is basically magic, but without all the magic

    • @Exahax101
      @Exahax101 3 ปีที่แล้ว +4

      It's logic not magic!

    • @SofronPolitis
      @SofronPolitis 3 ปีที่แล้ว +9

      That's why it's called mathemagics

    • @Felixrizzlord
      @Felixrizzlord 3 ปีที่แล้ว

      @@Exahax101 yes

    • @E12345E
      @E12345E 3 ปีที่แล้ว +5

      Given: Math is basically magic, but without all the magic
      Prove: Magic doesn’t exist
      math = magic Given
      math - magic = magic Given
      magic - magic = magic substitution POE
      0 = magic Simplify
      this proves that magic does not exist

    • @johnbiluke8406
      @johnbiluke8406 3 ปีที่แล้ว

      @@E12345E (YEAH, YOU IN THE CROWD, CAN YOU SPOT THE MISTAKE?)

  • @markdougherty8203
    @markdougherty8203 3 ปีที่แล้ว +40

    Method 3 is just completing the square from the other side. By symmetry it works the same. It's a cool trick though, because most people don't expect it. I have surprised people with it before. Obviously it's more convenient if the units term is a perfect square.

  • @idrisShiningTimes
    @idrisShiningTimes 3 ปีที่แล้ว +3

    I loved the first method honestly, since I'm basically used to solving fractions, and it gives out the answer in simplest form most of the time.

  • @AliKhanMaths
    @AliKhanMaths 3 ปีที่แล้ว +6

    I love the second way the most - looks so clean! You've really inspired me to share my maths tricks too!

  • @shuvo1562
    @shuvo1562 3 ปีที่แล้ว +1

    Type 3 seems new to me!Every time I learn something new from your videos.

  • @blackpenredpen
    @blackpenredpen  3 ปีที่แล้ว +14

    Do you have a different way to complete the square for this equation?

    • @ryancantpvp
      @ryancantpvp 3 ปีที่แล้ว +2

      No because the video is still premiering lol!

    • @purushothaman6698
      @purushothaman6698 3 ปีที่แล้ว

      No

    • @mathevengers1131
      @mathevengers1131 3 ปีที่แล้ว +10

      Fourth method: Use quadratic formula
      Fifth way: Tell πkachu to use thunderbolt

    • @beastgamer4932
      @beastgamer4932 3 ปีที่แล้ว +3

      how do you use quadratic formula to complete the square

    • @davidbrisbane7206
      @davidbrisbane7206 3 ปีที่แล้ว +8

      We can set x = 1/y, as x = 0 is not a solution.
      So, 2x² + 6x + 9 = 0 is transformed into
      9y² + 6y + 2 = 0
      So, 36y² + 24y + 8 = 0
      So, (6y + 2)² = -4
      So, 6y + 2 = ±2i
      So, 3y = -1 ± i
      So, y = (-1 ± i)/3
      So, x = 3/(-1 ± i)
      So x = (-3 ± 3i)/2

  • @paulg444
    @paulg444 3 ปีที่แล้ว +4

    This guy is the man!!!.. Love his energy!

  • @beaming_sparkling_trash261
    @beaming_sparkling_trash261 3 ปีที่แล้ว +3

    I'm in love w the third method

  • @juancarlosquispemamani7238
    @juancarlosquispemamani7238 3 ปีที่แล้ว +1

    Genial!!! yo soy de Bolivia voy en la carrera de Ingeniería y voy aprendiendo mucho de ti... muchas gracias por compartir tus conocimientos!!!! sigue adelante!!! exitos!!!

  • @tambuwalmathsclass
    @tambuwalmathsclass 3 ปีที่แล้ว +2

    I must try this in with my students

  • @prepa-maths
    @prepa-maths 3 ปีที่แล้ว

    Hello from France !!! Excellent channel !!

  • @patrickpablo217
    @patrickpablo217 3 ปีที่แล้ว +2

    Nice! All three were great :)
    I'll add another twist that can fit with any of the three. Recently I switched from "completing the square" to "completing the difference of squares" and I like it a lot more. I'll give a basic example:
    x^2+6x+8=0
    proceed as usual but *don't* move anything to the RHS:
    x^2 + 6x + 3^2 + -(3)^2 + 8 = 0
    (x + 3)^2 - ( 3^2 - 8 ) = 0
    that second term isn't a square yet but we can write it as one easily:
    (x + 3)^2 - (√[ 3^2 - 8 ])^2 = 0
    Now we have a difference of squares, but let's simplify first:
    (x + 3)^2 - (√[ 9 - 8 ])^2 = 0
    (x + 3)^2 - (√[ 1 ])^2 = 0
    (x + 3)^2 - (1)^2 = 0
    now difference of squares takes care of the ± automatically and gives
    (x+3+1)*(x+3-1)=0
    (x+4)*(x+2)=0
    so x={2,4}
    I really like this method since you never have to deal with moving things from LHS to RHS or back, and it's more like factoring, and it avoids the ± issue completely. It also has direct relation to the parabola associated with the quadratic: the first of the squares gives the line of symmetry (the x-coordinate of the vertex), and the second one provides the distance to the solutions and the y-coordinate of the vertex. And it saves steps, which is nice.

    • @patrickpablo217
      @patrickpablo217 3 ปีที่แล้ว

      for this equation 2*x^2 + 6x + 9=0:
      (doing more arithmetic than necessary, just to not get people lost)
      2*x^2+6x+(3/√2)^2 -(3/√2)^2 + 9 =0
      (√2*x+(3/√2))^2 - ((3/√2)^2 - 9) = 0
      (√2*x+(3/√2))^2 - (9/2 - 9) = 0
      (√2*x+(3/√2))^2 - (-9/2) = 0
      (√2*x+(3/√2))^2 - (i*3/√2)^2 = 0
      [so here next is where we use difference of squares (x^2 - y^2) = (x+y)*(x-y)]
      ( √2*x+(3/√2) + i*3/√2 ) * ( √2*x+(3/√2) - i*3/√2 ) = 0
      [group the constant terms:]
      (√2*x + (3+i*3)/√2)*(√2*x + (3-i*3)/√2)=0
      [you could be done here if you know that if (mx+n)=0 then x must equal -n/m, but if not, pull out a √2 from each factor:]
      √2*(x+(3+i*3)/2) * √2*(x+(3-i*3)/2)=0
      [combine them:]
      2*(x+(3+i*3)/2)*(x+(3-i*3)/2)=0
      Then we just read off the solutions as normal:
      x={ -3/2 -(3/2)*i, -3/2+(3/2)*i }
      which are the same as in the video

  • @SandeepKumar-dw3sj
    @SandeepKumar-dw3sj 3 ปีที่แล้ว +2

    Wow you have legend way to solve it

  • @MathAdam
    @MathAdam 3 ปีที่แล้ว +35

    Next video: 3 Ways to Complete the Pikachu

  • @Firefly256
    @Firefly256 3 ปีที่แล้ว +11

    Irrational Denominator to rational = rationalize
    Imaginary denominator to real = realize

  • @Raizensen9415
    @Raizensen9415 3 ปีที่แล้ว

    Best book for all basic concept for algebra

  • @danieleferrara561
    @danieleferrara561 3 ปีที่แล้ว

    Last one is the most interesting, thank you

  • @user-my7ki4it3s
    @user-my7ki4it3s 2 ปีที่แล้ว

    First one. But the other two ways were a completely new for me, thanks 😅

  • @nychan2939
    @nychan2939 3 ปีที่แล้ว +6

    I love the completing square method since I was a child.

  • @Songfugel
    @Songfugel 3 ปีที่แล้ว +5

    2nd one felt most comfortable, since it was close to the normal way to solve it

  • @anandk9220
    @anandk9220 3 ปีที่แล้ว +1

    Third method is the best of all time !!!
    😘😘😘😘😘😘😘😘😘😘

  • @durgeshverma8131
    @durgeshverma8131 3 ปีที่แล้ว +1

    Hey bro superior literally quite shocked to see the way you solved
    I'm in 11th and just now studies complex number with quadratic equations.😃😄😄
    LOVE from India

  • @krishanu-d1k
    @krishanu-d1k 2 ปีที่แล้ว

    First and second is best!!

  • @sueyibaslanli3519
    @sueyibaslanli3519 3 ปีที่แล้ว +1

    Exactly, the third one

  • @skyjumper4097
    @skyjumper4097 2 หลายเดือนก่อน

    1:00 where do the 3x go?

  • @jgrigg1720
    @jgrigg1720 3 ปีที่แล้ว +1

    I honestly love the third way.

  • @simdriver6797
    @simdriver6797 3 ปีที่แล้ว

    Mind blowing in t-3, t-2, t-1... now!

  • @aamirakhtar5913
    @aamirakhtar5913 3 ปีที่แล้ว +2

    We love your explanation 💘😻💜💛💚🧡 . Can you please tell us how you explain. When ever I try to explain any maths problem literally no one got it.
    You are awesome 👌

    • @in-ty8vb
      @in-ty8vb 3 ปีที่แล้ว

      I bet your explanation is good,they just don't know math

  • @muhammadnaufalzaky1326
    @muhammadnaufalzaky1326 3 ปีที่แล้ว +1

    Please, upload a video about the del operator, that thing in the vector calculus

    • @carultch
      @carultch 3 ปีที่แล้ว

      The del operator is a vector of partial differential operators. When applied to the next function, it is applied in a way that is analogous to either scalar multiplication, dot products, or cross products.
      Apply del to scalar field f(x,y,z), analogous to scalar multiplication, and we get the gradient of the scalar field. The gradient is a vector field of partial derivatives of the scalar field, which indicates the direction and magnitude of steepest ascent.
      del f(x,y,z) =
      Apply del dot to a vector field F(x,y,z), analogous to the dot product, and we get what we call the divergence. This is a measure of sources and sinks in a vector field. An application of this, is Gauss's law.
      del dot F = dF/dx + dF/dy + dF/dz
      Apply del cross to a vector field F(x,y,z), analogous to a cross product, and we get what we call curl. This is a measure of the rotationality of a vector field, and a vector field with a curl of zero is called a conservative vector field. A conservative vector field is the gradient of a scalar function. The curl of a vector field is itself a vector field, that will be perpendicular at every point. It indicates that line integrals around closed loops of a vector field are non-zero. An application of curl is Faraday's law of induction and Ampere/Maxwell's law of current and magnetic fields.

  • @reda4495
    @reda4495 3 ปีที่แล้ว

    Blackpenredpen >>>> any other math's teacher

  • @johnbiluke8406
    @johnbiluke8406 3 ปีที่แล้ว

    I like the Gatorade bottles in the background.

  • @mathstutors9179
    @mathstutors9179 3 ปีที่แล้ว +1

    7:35 What is the difference between “+or-“ and “-or+”

    • @Crash-yp7ll
      @Crash-yp7ll 3 ปีที่แล้ว +1

      If you have two or more of 'these' in eq, always use the top signs together or the bottom two signs together, but never the top and bottom of each together ...

    • @stephenbeck7222
      @stephenbeck7222 3 ปีที่แล้ว +2

      No difference if you only have one of them in the equation. Sometimes we write, for example, the formulas for sum and difference for cosines with a +- on one side and a -+ on the other side to indicate when one side is adding then the other side is subtracting and vice versa.

    • @Crash-yp7ll
      @Crash-yp7ll 3 ปีที่แล้ว +2

      Agree ... - '/ ' always confusing - Doesn't totally mean '+ or -' but maybe better as '+ and -, one at a time, and in that order' ...

  • @electrocode4095
    @electrocode4095 3 ปีที่แล้ว +20

    There is one another method (How you can forget Shri Dharacharya's Formula 🤨)
    ax² + bx + c = 0
    you can write
    x =( - b ⨦ √ (b² - 4*a*c) )/(2*a)

    • @flash.the.dash765
      @flash.the.dash765 3 ปีที่แล้ว +5

      Also known as the quadratic formula

    • @flash.the.dash765
      @flash.the.dash765 3 ปีที่แล้ว

      Apparently there are 3 ways

    • @AliKhanMaths
      @AliKhanMaths 3 ปีที่แล้ว +5

      Well-remembered! But that's just a derivation of the conventional completing the square method, so I don't think it would count as another method of completing the square.

    • @electrocode4095
      @electrocode4095 3 ปีที่แล้ว

      @Python Project Academy It can be able to make square just do some math for it
      i.e. after rearranging of variables and constant it would be (x+ b/2a)² = (b² - 4*a*c )/4*a²

    • @jimbobago
      @jimbobago 3 ปีที่แล้ว +2

      This formula is simply the generic result from using completing the square on ax^2 + bx + c = 0.

  • @mathysicssaransh7939
    @mathysicssaransh7939 3 ปีที่แล้ว +1

    Can u make a video explaining the graphical meaning of integration by substitution...more specifically .. integration by trigonometric substitution..?

    • @carultch
      @carultch 3 ปีที่แล้ว

      It means that you can recognize the integrand, as part of a term made from the Pythagorean theorem, in order to re-write a complicated term as a trig function that you can integrate.
      For instance:
      integral of dx/sqrt(1 - x^2)
      Draw a right triangle with (1-x^2) as one of its legs
      The remaining side will be x and the hypotenuse will be 1
      This enables you to define an angle on this triangle, in order for 1/sqrt(1-x^2) to be a trigonometric ratio of the angle you define.

  • @alpcanakaydn6986
    @alpcanakaydn6986 3 ปีที่แล้ว +13

    additional soluiton: if we multiply each side by 2 it becomes 4x²+12x+18=0 if we complete the perfect square it becomes (2x+3)²+9=0

    • @Leeanne750
      @Leeanne750 3 ปีที่แล้ว +2

      Multiplying by "4a" is safe. (In this case, 8). It will work all the time, not only in this example.
      ax^2 + bx +c =0
      4a^2x^2 + 4abx = -4ac
      (2ax + b)^2 = -4ac - b^2
      .........

    • @alpcanakaydn6986
      @alpcanakaydn6986 3 ปีที่แล้ว

      @@Leeanne750 It works just fine,but my goal is to find other solutions in the question

    • @angelofelisimolacruz1462
      @angelofelisimolacruz1462 3 ปีที่แล้ว

      @@Leeanne750 Thanks for this approach.

  • @migssir
    @migssir 3 ปีที่แล้ว

    Your 3rd solution is cool.

  • @qureshisiddig9274
    @qureshisiddig9274 3 ปีที่แล้ว

    How amazing is that you keep superise me wow

  • @3r3nite98
    @3r3nite98 3 ปีที่แล้ว

    This is very cool.

  • @nitish2799
    @nitish2799 3 ปีที่แล้ว

    1:31 How can a square of any no be -ve?

  • @glennn.micarandayo8657
    @glennn.micarandayo8657 3 ปีที่แล้ว

    Just curious of the formula table on the background

  • @denilsoncosta31415
    @denilsoncosta31415 3 ปีที่แล้ว

    Suggest 4th method to replace x by y-b/2a which is also cool.

  • @sakib5766
    @sakib5766 3 ปีที่แล้ว +3

    3rd method: when u r too crazy for a perfect square

  • @siralanturing9103
    @siralanturing9103 3 ปีที่แล้ว

    the cheeky smile when black pen says +/- but red pen says -/+

  • @EynkiYoom
    @EynkiYoom 3 ปีที่แล้ว

    Damn. Nice!!!!

  • @BlessingIduh
    @BlessingIduh 2 ปีที่แล้ว

    I prefer the third way

  • @kokichioma1408
    @kokichioma1408 3 ปีที่แล้ว

    I'm new subscriber here.

  • @willbishop1355
    @willbishop1355 3 ปีที่แล้ว

    I do really like the 3rd way, although as you said it won't always work.

  • @eliasmazhukin2009
    @eliasmazhukin2009 3 ปีที่แล้ว +10

    In fact, way #2 is the way people were doing it in India in the 11th century!

  • @MonzurulHoque3141
    @MonzurulHoque3141 3 ปีที่แล้ว +1

    & That's why I love Mathematics😍😍🤷😁😊😊

  • @daiyousei.1586
    @daiyousei.1586 3 ปีที่แล้ว

    This is so efficient holy sht
    Method 2 is my fav

  • @nory2441
    @nory2441 3 ปีที่แล้ว +1

    Hey bprp love from India nice videos can you plz make 100 limits in 1 take plz I commented before but u din't see

  • @sanadsingh7104
    @sanadsingh7104 3 ปีที่แล้ว

    Sir, can you tell me how to find the length of curve of sin x from 0 to pi

  • @noreldenzenky1527
    @noreldenzenky1527 3 ปีที่แล้ว +1

    perfect

  • @СвободныйУголок
    @СвободныйУголок 3 ปีที่แล้ว

    5:10
    incredible methods, but one thing I did not understand, why multiply by 8 in the 2nd method? can be multiplied by 2 and get the same result without huge calculations
    2(2х^2+6х+9)=0
    4х^2+12x+()^2=-18+()^2
    12=2*2*3
    (2x+3)^2=-18+9
    2x+3=+-r(-9)
    x=(-3+-3i)/2

    • @dog.3162
      @dog.3162 2 ปีที่แล้ว

      so it works consistently probably

  • @mokouf3
    @mokouf3 3 ปีที่แล้ว +1

    3rd way is cleanest.

  • @dr.rahulgupta7573
    @dr.rahulgupta7573 2 ปีที่แล้ว

    Sir (( d/dx) LHS )^2 = D , where D is discriminant of L HS function . This gives the answer immediately. i.e. (4x+6)^2 = -- 36 or 4x+6 = +6i or 4x +6 = --6i .

  • @aashsyed1277
    @aashsyed1277 3 ปีที่แล้ว

    Cool video! Thanks so much for these joyful moments ❤️nice work!

  • @bhgtree
    @bhgtree 3 ปีที่แล้ว +4

    "don't like fractions......when they see fractions 90% of them freak out." And thats only the teachers :)

  • @GDPlainA
    @GDPlainA 3 ปีที่แล้ว

    7:21 I cant unsee that -+ looking like a villager

  • @FaerieDragonZook
    @FaerieDragonZook 3 ปีที่แล้ว

    Since there is a constant term, x=0 is not a solution. Thus, you can divide both sides by x^2. Then make the substitution y = 1/x, and do complete the squares in y. This makes the third way look like the first

  • @omograbi
    @omograbi 3 ปีที่แล้ว

    There was a forth way you mentioned in other vids where you reduced the equation in a table and then multiplied the contents of the table.

  • @helloitsme3958
    @helloitsme3958 3 ปีที่แล้ว

    hey bro i need help
    1/a+a=b find 1/a^n+a^n in term b
    thanks

  • @robertveith6383
    @robertveith6383 ปีที่แล้ว

    *@ blackpenredpen* -- Treat the constant 3 as the variable from the start: 9 + 6x + 2x^2 = 0 --->
    (3)^2 + 2x(3) + ______ = -2x^2 + ______ ---> (3)^2 + 2x(3) + x^2 = -2x^2 + x^2 ---> (3 + x)^2 = -x^2.
    Then, proceed as you did with the rest of Method 3.

  • @ouidadelbojaddaini1432
    @ouidadelbojaddaini1432 3 ปีที่แล้ว

    How can we thank you?

  • @blackpenredpen
    @blackpenredpen  3 ปีที่แล้ว +36

    Try this cubic x^3-3x^2-3x-1=0
    Hint: it's kinda similar to the 3rd way in this video.
    Solution: th-cam.com/video/Jz-Z0jfs2V4/w-d-xo.html

    • @crispyclips6268
      @crispyclips6268 3 ปีที่แล้ว +3

      Bro can you please post some videos on calculus (majorly integral calculus) and functional equations too
      As I am preparing for jee advanced and the questions need practice for developing that approach.
      How to contact you ?

    • @crispyclips6268
      @crispyclips6268 3 ปีที่แล้ว

      And more questions like this one
      th-cam.com/video/3xzb-IqYDFk/w-d-xo.html

    • @4ltrz555
      @4ltrz555 3 ปีที่แล้ว

      @@crispyclips6268 he has made a lot of integration speedruns and long runs. You can check it out in his playlists

    • @crispyclips6268
      @crispyclips6268 3 ปีที่แล้ว

      OK thanks

    • @RazorM97
      @RazorM97 3 ปีที่แล้ว

      At 5:45 i thought you were going to say, "let's delete that two and it will work out nicely". Man I was so wrong XD

  • @johndanielvillanueva8604
    @johndanielvillanueva8604 3 ปีที่แล้ว

    Awesome

  • @PeetaN
    @PeetaN 3 ปีที่แล้ว

    I prefer the first that we can use everytime :)

  • @zerilioner639
    @zerilioner639 3 ปีที่แล้ว

    Hello, I have one math question:Find the equation of the tangent to
    the curve y =cos^2⁡ x when x=π/3 . Your solution should use radian
    measure. I kind of figured out m=-√3/2and y=1/4. Is the equation how to
    solve? Is it 1/4=√3/2(x-π/3)+y? Can you explain this question?

  • @StephanvanIngen
    @StephanvanIngen 3 ปีที่แล้ว

    Beautiful

  • @thengodpbot7892
    @thengodpbot7892 3 ปีที่แล้ว

    can you do IMO 2021

  • @professoraxolotl8960
    @professoraxolotl8960 3 ปีที่แล้ว

    3:58 I'm a math teacher and the same thing happens to me quite a lot, I want to ask for something but I say the answer hahaha

  • @prashanthkumar0
    @prashanthkumar0 3 ปีที่แล้ว

    all the methods were good but i still like quadratic formula :P

  • @particleonazock2246
    @particleonazock2246 3 ปีที่แล้ว

    Just if you didn't know: bprp drilled a square peg in the round hole of his Pokeball. This enabled him to complete the square, in his niche field of mathematics.

  • @aryangupta7092
    @aryangupta7092 3 ปีที่แล้ว

    Can u find the remainder when 17^(63) is divided by 1000

  • @arshadalam
    @arshadalam 3 ปีที่แล้ว +2

    Simply use quadratic formula

  • @GDPlainA
    @GDPlainA 3 ปีที่แล้ว +1

    the 2nd way is basically going from the quadratic formula to the base form

  • @rikthecuber
    @rikthecuber 3 ปีที่แล้ว +1

    DO SOME DIFFERENTIAL EQNS BPRP!

    • @blackpenredpen
      @blackpenredpen  3 ปีที่แล้ว +2

      What's a differential equation?
      jk, here's the diff eq marathon: th-cam.com/video/e-cTygNbEUE/w-d-xo.html

    • @durgeshverma8131
      @durgeshverma8131 3 ปีที่แล้ว

      He means to use calculus method.

  • @ericthecuberspeedcuber
    @ericthecuberspeedcuber 3 ปีที่แล้ว

    5:46 "Wouldn't it be nice"

  • @blandon93
    @blandon93 3 ปีที่แล้ว

    Is there a way where one of x is equal to i or -i? I calculated one imaginary root which is close to -i (like -0,98i), I wonder if we ever can achieve whole i number.

    • @flash.the.dash765
      @flash.the.dash765 3 ปีที่แล้ว

      The letter 'i'is basically an imaginary number since its not possible to solve the negative root. However if you write it as '-i' it'll simply cancels the negatives of root and the letter i and results in positive root

    • @MohammadIbrahim-sq1xn
      @MohammadIbrahim-sq1xn 2 ปีที่แล้ว

      =(x+i)(x+k)
      =x²+x(i+k)+ ik

  • @XAHMED5A
    @XAHMED5A 3 ปีที่แล้ว

    prove that from L.H.S (secA.secB.cscA.cscB)/(cscA.cscB - secA.secB) = sec(A+B)

  • @thengodpbot7892
    @thengodpbot7892 3 ปีที่แล้ว

    Do you know general way to complete cube equation

  • @matejcataric2259
    @matejcataric2259 3 ปีที่แล้ว

    I love math4fun and I love bprp and I love math

  • @egorsuzopov2419
    @egorsuzopov2419 3 ปีที่แล้ว

    Good day. Here in Russia we solve that equations in school way with Discriminant, which is: D = b^2 - 4ac. And the x1 & x2 = (- b ± i*√D)/2a. Much faster!

    • @chitramc7238
      @chitramc7238 3 ปีที่แล้ว

      Same

    • @robertveith6383
      @robertveith6383 ปีที่แล้ว

      Write 2a inside of parentheses when it is in the denominator.

  • @eipimath
    @eipimath 2 ปีที่แล้ว +1

    Thanks for sharing! I posted a video on completing the square using remainder theorem. Hope to get your opinion on it.

  • @MathNerd1729
    @MathNerd1729 3 ปีที่แล้ว

    I just found out how the last way generalizes! It's quite fun! :)
    Start with:
    ax² + bx + c = 0 (c ≠ 0)
    Move the ax² term:
    bx + c = -ax²
    Multiply by 4c:
    4bcx + 4c² = -4acx²
    Add b²x² and factor:
    b²x² + 4bcx + 4c² = (b² - 4ac)x²
    (bx + 2c)² = (b² - 4ac)x²
    Take the square root:
    bx + 2c = ± √(b² - 4ac) x
    Solve for x and rationalize the denominator to get the usual Quadratic Formula! :)
    Footnote: Apologies to BPRP about my previous comment; I meant the last way and didn't know how to tell you I made a typo!
    Additional note: The formula we get before rationalizing the denominator is known as the citardauq formula (That's quadratic backwards!)

  • @klausbuda7922
    @klausbuda7922 3 ปีที่แล้ว +1

    I would use the quadratic equation to solve it

    • @jimbobago
      @jimbobago 3 ปีที่แล้ว

      But you need completing the square to develop the quadratic formula in the first place.

  • @kcfish4862
    @kcfish4862 3 ปีที่แล้ว +1

    Yooo I didn't even know you are Taiwanese, you watching Olympics?

  • @irfanali8366
    @irfanali8366 3 ปีที่แล้ว

    Sir I have a question why this equation is equal to zero?

  • @Bonthefanfan
    @Bonthefanfan 3 ปีที่แล้ว

    #bprp, can u do 100 series, but this time is product summation.

  • @pp-ey2ru
    @pp-ey2ru 3 ปีที่แล้ว +1

    4th way is use the formular

  • @DudsO_o
    @DudsO_o 3 ปีที่แล้ว

    although hating fractions, I prefer the first one

    • @chocolateangel8743
      @chocolateangel8743 3 ปีที่แล้ว +1

      If you hate fractions, you should check out the fraction series that Dr. James Tanton has on his channel. He's a mathematics educator and researcher that's big on teaching the mathematical logic and concepts behind things. He believes that the more a student understands, the less he or she has to memorize. He deals with fractions differently than most people.

  • @arcader30
    @arcader30 3 ปีที่แล้ว +2

    4th way, use QUADRATIC FORMULA!! 😁😁

    • @jimbobago
      @jimbobago 3 ปีที่แล้ว

      But the only reason the quadratic formula exists is ... completing the square ... which is the point of the video.

  • @simplevc2980
    @simplevc2980 3 ปีที่แล้ว

    First way

  • @DownDance
    @DownDance 3 ปีที่แล้ว +1

    I like that you say with multiply everybody... Like these are humans

  • @marbangens
    @marbangens 3 ปีที่แล้ว

    the 3rd way, because 1+1 is fun :)

  • @holyshit922
    @holyshit922 3 ปีที่แล้ว

    For cubic equation
    ------------------------------------------
    In book written in my native language in XVIII century
    there is following way
    Let's start from equation
    x^3+px+q=0
    Move terms with x and constant to the other side
    x^3=-px-q
    Let's complete cube with free variable
    x^3+3x^2z+3xz^2+z^3=3x^2z+3xz^2+z^3-px-q
    (x+z)^3=(3xz+3z^2-p)x+z^3-q
    Now suppose that
    3xz+3z^2-p=0
    3z(x+z)=p
    x+z=p/(3z)
    p^3/(27z^3)=z^3-q
    z^6-qz^3-p^3/27=0 and we have quadratic in z^3
    Interesting way for cubic which I saw on math forum
    uses sum of cubes identity
    x^3+px+q=A(x+m)^3+B(x+n)^3
    Expand these cubes , compare coefficients and you will get system of equations to solve

  • @karma_kun9833
    @karma_kun9833 3 ปีที่แล้ว

    (Odd+Odd+Odd=Even)?
    Can we prove that's right or not?