How do you calculate 3(cos14^circ+isin14^circ)*2(cos121^circ+isin121^circ)?

1 Answer
Apr 6, 2017

Multiplication this type is defined as:

r_1(cos(theta_1)+isin(theta_1)*2(cos(theta_2)+isin(theta_2)=r_1r_2(cos(theta_1+theta_2)+isin(theta_1+theta_2))

Explanation:

In this case, r_1 = 3, r_2 = 2, theta_1 = 14^@", and "theta_2 =121^@:

3(cos14^circ+isin14^circ)*2(cos121^circ+isin121^circ) = 6(cos(135^@)+isin(135^@))

This simplifies to:

-3sqrt2+3sqrt2i