Write a function called mat vec() that takes as input a square matrix and a vector of compatible dimensions, and returns the resulting product vector. That is, if the input are an n n matrix A and an n1 vector x, then mat vec(A,x)= Ax. Test your function on small matrices and vectors that you can check by hand. When you are satisfied, move on to parts (b) and (c). Additionally, print out your code for this function and include it with your assignment.