Multiplication
Like a vector, there are many ways to multiply a matrix. In this chapter we will cover multiplying matrices by a scalar or by another matrix. Scalar multiplication is component wise. Given a matrix M and a scalar s, scalar multiplication is defined as follows:
We can also multiply a matrix by another matrix. Two matrices, A and B, can be multiplied together only if the number of columns in A matches the number of rows in B. That is, two matrices can only be multiplied together if their inner dimensions match.
When multiplying two matrices together, the dimension of the resulting matrix will match the outer dimensions of the matrices being multiplied. If A is an matrix and B is an matrix, the product of AB will be an matrix. We can find each element of the matrix AB with the following formula:
This operation concatenates the transformations represented by the two matrices into one matrix. Matrix multiplication is not cumulative. . However, matrix multiplication is associative...