Question

I need help multiplying matrices please?

Answer 1

Whatever the answers are, multiply the given pair of matrices. If their product is the identity matrix, then the matrices are inverses of each other.

Answer 2

A.\[\left[\begin{matrix}1/3 & 4 \\ 2 & -1/2\end{matrix}\right] and \left[\begin{matrix}-1/3 & -4 \\ -2 & 1/2\end{matrix}\right]\]B.\[\left[\begin{matrix}4 & 4 \\ 8 & 10\end{matrix}\right] and \left[\begin{matrix}5/4 & -1/2 \\ -1 & 1/2\end{matrix}\right]\]C.\[\left[\begin{matrix}5 & 8 \\ 5 & 10\end{matrix}\right] and \left[\begin{matrix}1/2 & -4/5 \\ -1/2 & 1\end{matrix}\right]\]D.\[\left[\begin{matrix}6 & 3 \\ 8 & 6\end{matrix}\right] and \left[\begin{matrix}1/6 & -1/3 \\ -1/8 & 1/6\end{matrix}\right]\]

Answer 3

That's the problem, I'm not quite sure how to multiply them.

Answer 4

I know they have to equal\[\left[\begin{matrix}1 & 0 \\ 0 & 1\end{matrix}\right]\]

Answer 5

Say you have two matrices to multiply:
\[\begin{bmatrix}a&b\\c&d\end{bmatrix}\text{ and }\begin{bmatrix}e&f\\g&h\end{bmatrix}\]
Their product is then
\[\begin{bmatrix}ae+bg&af+bh\\ce+dg&cf+dh\end{bmatrix}\]

Answer 6

I figured it out lol thank you though