# Math Help - Value of Argz

1. ## Value of Argz

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.

2. Recall that cosine is an even function and sine is an odd function.
So $\cos \left( {\frac{\pi }{5}} \right) - i\sin \left( {\frac{\pi }{5}} \right) = \cos \left( { - \frac{\pi }{5}} \right) + i\sin \left( { - \frac{\pi }{5}} \right)
$
.