At 1:38 I was confused. Why do you flip the -3 & -7 and why do only the 6 & 8 become negative in their same position. Also.. how did you get the 1/21-48?
What he forgot to tell you is: a sub 11 = a; a sub 12 = b; a sub 21 = c; a sub 22 = d. So the formula he's using when says determinate is: 1/ad-bc[ ...]
This will work on any square coefficient matrix, but it’s a little more challenging to find the inverse matrix if it’s larger than 2x2. But still very doable.
@@vivekcharan2587 sure the -1/27 was used to multiply everything inside the matrix. So multiply -1/27 * -6 = 6/27 which is reducible fraction. They have a common factor of 3 so I divided by 3 and it reduces to 2/9
Thank you so much. This is really helpful.
you made my quiz go from 4/9 to 7/9. huge.
Thank you, this was very clear and helpful.
dab
At 1:38 I was confused. Why do you flip the -3 & -7 and why do only the 6 & 8 become negative in their same position. Also.. how did you get the 1/21-48?
It's the definition of the inverse matrix, and the determinant.
What he forgot to tell you is: a sub 11 = a; a sub 12 = b; a sub 21 = c; a sub 22 = d. So the formula he's using when says determinate is: 1/ad-bc[ ...]
Thanks a lot man. Appreciate it👍
yourwelcome
Does this only work on a 2x2 coefficient matrix?
This will work on any square coefficient matrix, but it’s a little more challenging to find the inverse matrix if it’s larger than 2x2. But still very doable.
How is 6 into 27. 2 over 9
6/27 divide by 3 to simplify and you get 2/9
@@guyrieirving2993 how is it possible man could you please explain me
@@vivekcharan2587 sure the -1/27 was used to multiply everything inside the matrix. So multiply -1/27 * -6 = 6/27 which is reducible fraction. They have a common factor of 3 so I divided by 3 and it reduces to 2/9
Thanks bro.....
you help me a lot.
wallah i love u bro
JazakAllah
INTERESTING
how about detA=0 ?
then there is no inverse. you can tell if there's no inverse if a row or column are all zeros.
I love linear algebra!
Hlw I m an Indian
its wrong