Hey guys, just another question on complex numbers:

z = cos36 - isin36, State the values of absolute z and Argz

Okay, so this is how far i can get:

z = cos(pie/5) - isin(pie/5)

z = cos(pie/5) + i(-sin(pie/5))

From there im not to sure what to do, since the sin value is negative. Please explain working out.