You should always give out as much information related to your question as you can. Help us to help you. I did not completely understand what you mean by representing angles in MATLAB. It is extremely vague. Do you mean rotation matrix? If yes, then it is given by (for a 3 x 3 case)
R = [ 1 0 0
0 cos(theta) sin(theta)
0 -sin(theta) cos(theta)]
The theta is in radians. How did you get the matrix that you have for 45 degrees?