Question

If 3+3i and z2=7(cos(5pi/9)+isin(5pi/9)), then z1z2=____?

A. 21sqrt2(cos(5pi/36)+isin(5pi/36))

B. (3sqrt2/7)(cos(-11pi/36)+isin(-11pi/36))

C. 21(cos(5pi/36)+isin(5pi/36))

D. 21sqrt2(cos(29pi/36)+isin(29pi/36))

I think it's supposed to say if Z1=3+3i, but I'm not entirely sure. How do?

Answer 1

`I think it's supposed to say if Z1=3+3i`

sounds like it

Answer 2

z1 = 3+3i is in the form a+bi

a = 3
b = 3

r = sqrt(a^2 + b^2) = ???

theta = arctan(b/a) = ???

Answer 3

Ran out of time, the answer was D.