Reflection/Rotation Matrices

Hi, i'm quite confused, i'm working out all the reflections/rotations for a regualr pentagon.

I was wondering if someone could help with the matrices;

So the rotation matrix is (cos# -sin#, sin# cos#)

Where # is the angle, and my angles are 2pi/5, 4pi/5, 6pi/5, 8pi/5, 2pi - the identity

Do I simply enter my values of pi into the above matrix and that is all that's required?

Then the reflection matrix is (cos# sin#, sin# -cos#)

Once again do I just enter my values of pi?

Many thanks in advance to whoever replies!