The matrix inverse M^-1 now appears in cells E8:G10. Now we are ready to multiply both sides of our matrix equation by M^-1.

Multiplying the matrices M^-1 and M results in the identity matrix, which has 1's on the diagonal and 0's everyplace else. To verify this, we next use the function MMULT() for matrix mutilplication. We will multiply two 3-by-3 matrices and the answer is a 3-by-3 matrix. So it's another array formula. So we make space for the answer (I8:K10), enter =MMULT(A8:C10,E8:G10) in the formula bar and then CRTL+SHIFT+ENTER.

This is just a test and really doesn't have to be done.

NEXT
BACK