Question

Given z1 = 24(cos 315° + isin 315°) and z2 = 3(cos 120° + isin 120°), what is the product of z1 and z2?

Answer 1

Answer:

72(cos 75° + isin 75°)

Step-by-step explanation:

$\boxed{z_1\times z_2=r_1\cdot r_2(cos(\theta_1+\theta_2)+isin(\theta_1+\theta_2))}$

$z_1\times z_2=24\times3(cos(315^o+120^o)+isin(315^o+120^o))$

           $=72(cos\ 435^o+isin\ 435^o)$

           $=72(cos\ 75^o+isin\ 75^o)$