Question

(cos(3x)+isin(3x))/(cos(x)+isin(x))

Answer 1

Given expression is: $\frac{(cos(3x)+isin(3x))}{(cos(x)+isin(x))}$

Using Euler form, this can simplify to: $\frac{e^{i(3x)}}{e^{i(x)}}\\$

$=e^{i(2x)}\\ =cos(2x)+isin(2x)$