What's wrong with this code?

Dear fellows. I was asked to create a function for which the input is a matrix M(n,m) and the output is also a matrix, Q(n,m), so that Q(n,m) is sin (M(n,m)) if M(n,m) is even and Q(n,m) is cos (M(n,m)) if M(n,m) is odd. That's what I did:

function [Q] = myTrigOddEven(M)
n = size(M,1);

m = size(M,2);

for i = 1:n

      for j = 1:m

          if rem(M(n,m),2)== 0
              Q(n,m) = sin(M(n,m))
          else
                Q(n,m) = cos (M(n,m));
          end

      end

end

I tested it with the matrix A = [1 2; 3 4] but I got [0 0 ; 0 -0.7568] as a result. What did I do wrong?

Answer 1

[the cyclist]

In these lines, you should be indexing with (i,j) rather than (n,m)

if rem(M(n,m),2)== 0
    Q(n,m) = sin(M(n,m))
else
    Q(n,m) = cos (M(n,m));
end