I was so confused at first because I know that is not how I learned it in my other classes, but after the second time watching it I found it to be so much easier. Thank you for this video!
So glad I watched this before going into the final!! I understood how to solve this in my calculator, but was having a hard time grasping how to calculate the determinant of 3 x 3 matrices without it. Thanks for sharing!
My teacher used an extremely long and confusing method to solve this type of question. You solved it in 2 minutes. You may just be the best teacher I’ve never had…
In mathematical notation, when we put the letter that represents the matrix between vertical lines, it means find the determinant. It looks like absolute value notation, but absolute value versus determinants is like comparing apples and oranges.
After seeing this i understand much better how to not rely blindly on my handy dandy TI-84 graphing calculator although it is quite an useful tool. If i ever happen to find myself trying to gain access to ancient Greek city of Thebes as Oedipus once did, the Sphinx will surely ask me this as the riddle, and i am thankful for having learned this for i shall have nothing to fear on my journey.
@NGViral The method does work for the matrix... 1 0 1 0 2 1 1 1 1 When you recopy the first two columns and juxtapose them with the original matrix, you get... 1 0 1 1 0 0 2 1 0 2 1 1 1 1 1 Multiply from upper left to lower right, you get 2 + 0 + 0 = 2 Multiply from upper right to lower left, you get 2 + 1 + 0 = 3 Now subtract 2 - 3 and you get -1. Hope this helps.
Thank you! In my math classes it was referred to as "spaghetti math" and we did it so often that I only wrote it down once. Can't find the note now, but you covered it perfectly!
Yes, although when you're finding a cross product and set it up in "determinant" form, it's not a real determinant but a device to help remember the formula for the cross product of two vectors.
For a 4*4 matrix you can use the gauss jordan method, which works for any nxn matrix. As for 3*4 matrices, they have no determinant. Determinant is a quantity associated with square matrices only ( ie n*n matrices)
If you plan to do Differential Equations, this is the way to go folks, not the usual 3 part (+ - +) equation. Even though my teachers for Statics, Dynamics and Differential Equations used this method, I persisted in using the equation I was taught because that's what I had practiced. It works fine for me until I had to find eigen values in DE where you have some 2-term multiples in a 3x3 matrix. During the stress of my third test, I kept making Alg. mistakes in working out the equation method, so I could never find my eigen values which is only the first step in the problem which was worth 15 points. Since my teacher gives partial credit, I showed him I knew how to do the rest of the problem by giving the eigen values variables and then showing him what I would do if the values were distinct & real or if the values were repeated (the third "unreal" values possibility was already demonstrated on another problem on the test). He graciously gave me 12 out of the 15 points. Studying for the final now and I'm finally trying this and seeing how much easier it is. .... The End
this was the "trick" i was looking for but honestly, cofactor expansion is just easier for me. I always forget the signs on this one. the signs on cofactor expansion are easier to remember for me
How did I calculate 2 x 0.5 x 5? It's just arithmetic that the product of those numbers is "5". Similarly, 7 x 0.5 x 6 is 21 just as we learned in basic arithmetic.
I have few questions . 1-What exactly is a domain in 4 number matrix showing us? (I think in 3 number it could be volume but 4th and higher?! Time-space...) Please clarify. 2-in three number what each set shows? Coordinates? Do we put x coordinates in one row? Thank you.
@nz109304 This method is perfectly acceptable providing that it is a 3 x 3 matrix. Anyone who passed an elementary linear algebra course would know that. However, it would be wrong to attempt this on a 4 x 4 matrix, for example. Cofactor expansion is the proper methodology for a general n x n matrix.
@JimmyFox01. The purpose of the determinant is to determine whether of not a matrix has an inverse: A matrix has an inverse if and only if its determinant is not zero.
to find the eigenvalues of a 3 by 3 matrix can i reduce the matrix to row echlon form and subtract lambda from the diagonal then multiply the diagonlas across
@jcpotter56 Actually, the numbers you see in the matrix represent coefficients, so those numbers you have on the right side of the 3 equations you wrote would really be coefficients on the variable "z".
This is very right its very correctand i even learn it at school. it will come in my quiz tomorrow :) thank goodness it's easy because of this video. I have the worst teacher for algebra. the teacher's explanation is sooooo hard and the teacher doesn't want questions :S
Is this really work? I just checked the answer by doing it in proper way, it didn't give same answer as you gave and I've never heard about cramers rule. Can you give a example that compares answer by doing cramers rule and one that doesn't or proof of cramers rule? because I think cramer's rule is wrong
what he did wrong was you are supposed to add the same diagnols and subtract the other ADDED diagnols he subtracted the SUBTRACTED diagnols if you get what i mean
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2 semesters with this professor. One of the best math professors I've had. Would definitely take again.
This is a very straight forward example of solving for the determinant of a 3x3 matrix, I'm sure it will come in handy in the near future. Thank you.
Simple and straight forward walk through, thank you for the help!
I was so confused at first because I know that is not how I learned it in my other classes, but after the second time watching it I found it to be so much easier. Thank you for this video!
So glad I watched this before going into the final!! I understood how to solve this in my calculator, but was having a hard time grasping how to calculate the determinant of 3 x 3 matrices without it. Thanks for sharing!
My teacher used an extremely long and confusing method to solve this type of question. You solved it in 2 minutes. You may just be the best teacher I’ve never had…
14 years later and this method saved a new a level student, thx prof!
In mathematical notation, when we put the letter that represents the matrix between vertical lines, it means find the determinant. It looks like absolute value notation, but absolute value versus determinants is like comparing apples and oranges.
After seeing this i understand much better how to not rely blindly on my handy dandy TI-84 graphing calculator although it is quite an useful tool. If i ever happen to find myself trying to gain access to ancient Greek city of Thebes as Oedipus once did, the Sphinx will surely ask me this as the riddle, and i am thankful for having learned this for i shall have nothing to fear on my journey.
With this tutorial now i do not have to rely on the calculator. Awesome.
this formula is going to save me a lot of time on my exam! Thanks bro;)
I wish you would put up a course on matrices.....love the way you teach and diagrams are excellent
It is a shortcut for 3x3 systems only. One could also do cofactor expansion, which would be applicable to any old system, 3x3 or otherwise.
@NGViral The method does work for the matrix...
1 0 1
0 2 1
1 1 1
When you recopy the first two columns and juxtapose them with the original matrix, you get...
1 0 1 1 0
0 2 1 0 2
1 1 1 1 1
Multiply from upper left to lower right, you get 2 + 0 + 0 = 2
Multiply from upper right to lower left, you get 2 + 1 + 0 = 3
Now subtract 2 - 3 and you get -1.
Hope this helps.
I was looking for this kind of tutorial! Thank you so much! :)
Thank you, this method is so much more simple than what they teach us in the textbook.
Rest in peace Harambe.
Great video professor, this was very helpful! Thank you very much
Thank you! In my math classes it was referred to as "spaghetti math" and we did it so often that I only wrote it down once. Can't find the note now, but you covered it perfectly!
This video helped me understand the topic a lot more. Thank you professor !
Yes, although when you're finding a cross product and set it up in "determinant" form, it's not a real determinant but a device to help remember the formula for the cross product of two vectors.
Your solution is wayy simplier and easier than the teacher taught in my univ.. Thank you so much this will help me alot in my exams
I love this guy! He makes math fun!! I'm taking calculus and he really knows how to explain the material.
dunno what was so fun in the this video it was fine but cant say fun
This isn't even calculus , it's algebra, tf ?
Samei Micale hello
are you engineer
This was very helpful, thank you Professor!
hamm
.
Great video, professor! Very helpful and now I feel ready for the final exam!
@abarashyasir1 It only works for 3 x 3 matrices. For 10 x 10, you would have to use something like cofactor expansion (or a graphing calculator).
This material is golden
Thanks for the video! My favorite way of calculating the determinant for a 3x3 matrix yet I always forget it lol
This is a big help for the test tomorrow thanks.
Easier method than the one I was previously thought.
this video really helped me, thank you professor
I'm trying to learn this from 6 weeks.Now I got it sir
sir very very nice. you created a new idea very easy
God Bless you
Great way to explain this concept!
Thanks, this this is a great technique and helped a lot.
This was very helpful! Thank you very much this saved me for my test tomorrow!
i forgot how to solve determinants. this video helps me to remember.
thanks a lot. i made it. i remember now
Awesome! After watching this video I'm ready for the easy final exam! I won't have to pray to the rabbit God for help
Ohhh so that's how you do that, I think i missed a bit of that on my notes and was a bit confused thank you professor that makes it much easier.
finally i found it here. its not even in the text book. Thank you very much.
Thank you professor! -Mendelina Lopez
For a 4*4 matrix you can use the gauss jordan method, which works for any nxn matrix. As for 3*4 matrices, they have no determinant. Determinant is a quantity associated with square matrices only ( ie n*n matrices)
Great video, i feel ready for my final exam now!!
If you plan to do Differential Equations, this is the way to go folks, not the usual 3 part (+ - +) equation. Even though my teachers for Statics, Dynamics and Differential Equations used this method, I persisted in using the equation I was taught because that's what I had practiced. It works fine for me until I had to find eigen values in DE where you have some 2-term multiples in a 3x3 matrix. During the stress of my third test, I kept making Alg. mistakes in working out the equation method, so I could never find my eigen values which is only the first step in the problem which was worth 15 points. Since my teacher gives partial credit, I showed him I knew how to do the rest of the problem by giving the eigen values variables and then showing him what I would do if the values were distinct & real or if the values were repeated (the third "unreal" values possibility was already demonstrated on another problem on the test). He graciously gave me 12 out of the 15 points. Studying for the final now and I'm finally trying this and seeing how much easier it is. .... The End
thank you! hopefully it will help me with my exam tomorrow
Why did you subtract all of the red numbers instead of adding them like you did the green?
Bro, are you alive? And I hope you got an answer for your question
I found this Helpful for tomorrow test, thanks. Antonio Munguia
thanks for the informative video, you really helped me out
Well explained and helpful!
thaaaaaaaaaank youuuu he even explained it better than my teacher
Prof. This trick is really work..??
perfectly explained, thank you sir.
this was the "trick" i was looking for but honestly, cofactor expansion is just easier for me. I always forget the signs on this one. the signs on cofactor expansion are easier to remember for me
SHUT UP NERD - PUSHES U INTO A LOCKER- GIMME UR LUNCH MONEY KID!
would you please be able to make a video on how to find a variable in matrix? thanks
So helpful making it seem way easier than my lecturer haha
Great video really helped me with my work! My name Aaron Baltazar im in your Math 101 class at 1030 TTh
great trick, but what is the application of the determinant, i mean how can we use it?
it's 1:30 am and god bless this video for all it's worth
You've explained well. Thank you.
How did I calculate 2 x 0.5 x 5? It's just arithmetic that the product of those numbers is "5". Similarly, 7 x 0.5 x 6 is 21 just as we learned in basic arithmetic.
Cool! Ready for the exam now! Thanks.
I really thanks u for ur teaching.
Great video professor!
I have few questions . 1-What exactly is a domain in 4 number matrix showing us? (I think in 3 number it could be volume but 4th and higher?! Time-space...) Please clarify.
2-in three number what each set shows? Coordinates? Do we put x coordinates in one row?
Thank you.
Thanks for the tips Professor.
Thanks! This makes it much faster when trying to solve a system of equations!
@nz109304 This method is perfectly acceptable providing that it is a 3 x 3 matrix. Anyone who passed an elementary linear algebra course would know that. However, it would be wrong to attempt this on a 4 x 4 matrix, for example. Cofactor expansion is the proper methodology for a general n x n matrix.
Thanks for this video. It helped me a lot
@JimmyFox01. The purpose of the determinant is to determine whether of not a matrix has an inverse: A matrix has an inverse if and only if its determinant is not zero.
to find the eigenvalues of a 3 by 3 matrix can i reduce the matrix to row echlon form and subtract lambda from the diagonal then multiply the diagonlas across
Thanks man. That was really helpful. Nice job👍👍
Thanks for sharing Professor!
@JimmyFox01
It can be used, for example, in Cramer's Rule (i.e. solving a system of linear equations multiple unknowns.)
Can I use this technique for 5 by 5 matrix ?
Is it valid for only 3*3 matrix..or any order matrix?
Amazing video very well done. also very very neat handwriting.
Thank you very much . Great explanation
very well done and nicely explained
10/10
@jcpotter56 Actually, the numbers you see in the matrix represent coefficients, so those numbers you have on the right side of the 3 equations you wrote would really be coefficients on the variable "z".
Woah! Your good
As promised! I've watched the video and I'm leaving a comment. This is neither good nor a bad comment, but - is it too late for extra credit?
the way I learned it was like this, except that there are supposed to be parentheses around the "red" values. Don't know if that changes anything....
Great video, very helpful
That's the general formula for finding the determinants of matrices. This is just a faster way of solving 3x3 matrices specifically.
Thanks, really helped with my Calculus. I forgot how to do it.
This is very right its very correctand i even learn it at school. it will come in my quiz tomorrow :) thank goodness it's easy because of this video. I have the worst teacher for algebra. the teacher's explanation is sooooo hard and the teacher doesn't want questions :S
@NGViral It does work for this matrix. Carefully check your arithmetic.
How are ya? Awesome helpful video!
Hey professor great video!
can you do this with a 4x4 or 5x5 or more?
Thanks alot !! Really helped me out.
this helped so much thank you!
ye but what is the theory behind it
Is this really work? I just checked the answer by doing it in proper way, it didn't give same answer as you gave and I've never heard about cramers rule. Can you give a example that compares answer by doing cramers rule and one that doesn't or proof of cramers rule? because I think cramer's rule is wrong
Is the result valid for 4×4??
what he did wrong was you are supposed to add the same diagnols and subtract the other ADDED diagnols he subtracted the SUBTRACTED diagnols if you get what i mean
sooo would the equation from the beginning(Q=) be
2x-4y=7
8x+1/2y=3
6x-9y=5 ...?
need an answer fast plz!
wouldnt it just be 378 cuz its absolute value??? im confused
i was told to multiply the colors that are the same, then subtract them from the different color for the determinate?
What if we open by 2nd row or maybe 3rd
Thank you sir that was Great help, I can do my assignment now.