Question 1044593
The rows (or columns) of A constitute an orthonormal set of vectors (i.e., any pair is orthogonal, or has scalar product 0; and each has magnitude 1.)  
Therefore the inverse of A will just be its transpose {{{A^T}}}.

===> {{{A^(-1) = A^T = (matrix(3,3, cosQ, -sinQ, 0, sinQ, cosQ, 0, 0,0,1))}}}.

Feel free to verify that {{{A*A^T = A^T*A = I[3]}}}.