(no subject)
God damn it, Ms. Cerrone!
Ke, Ony, remember in HL math 2 when she tried to teach us how to invert a matrix, and none of us really knew what was going on and we basically just had to apply arbitrary rules? Well, in my linear algebra class today I learned why it works that way. Sigh.
So when multiplying matrices, some matrix by the one you're interested in [A], say, the rows of the answer are each linear combinations of the rows of [A], depending on the rows of the first matrix. So to solve a matrix, you take the upper left value and use that row in linear combination with each of the rows below to get rid of all the other numbers in the first column. This gives you some matrix times A. Then you do the same starting with a_2,2, etc. And each row you change gives you an identity matrix with one extra number. So eventually you multiply all the transformation matrices together, and that's the inverse.
Why the hell couldn't ms. cerrone have explained that instead of confusing a whole class???
Supid woman. Sigh.
Ke, Ony, remember in HL math 2 when she tried to teach us how to invert a matrix, and none of us really knew what was going on and we basically just had to apply arbitrary rules? Well, in my linear algebra class today I learned why it works that way. Sigh.
So when multiplying matrices, some matrix by the one you're interested in [A], say, the rows of the answer are each linear combinations of the rows of [A], depending on the rows of the first matrix. So to solve a matrix, you take the upper left value and use that row in linear combination with each of the rows below to get rid of all the other numbers in the first column. This gives you some matrix times A. Then you do the same starting with a_2,2, etc. And each row you change gives you an identity matrix with one extra number. So eventually you multiply all the transformation matrices together, and that's the inverse.
Why the hell couldn't ms. cerrone have explained that instead of confusing a whole class???
Supid woman. Sigh.