If A is a 2X2 matrix, a12 = a21 = 0, a11 ≠ 0, a22 ≠ 0 then show that A is regular and find A^-1.
Many thanks in advance.
Um, I know that a matrix has an inverse if the determinant is nonzero. Is that right?
I usually know how to find the determinant and the inverse but I just can't do it when the matrix isn't written out.
Could you help me figure out what the original matrix is?