How do you use DeMoivre's theorem to simplify (5e^(15i))^3(5e15i)3?

1 Answer
Nov 7, 2016

The answer is =125(cos45+isin45)=125(cos45+isin45)

Explanation:

DeMoivre theorem states that
(costheta+isintheta)^n=cosntheta+isinntheta(cosθ+isinθ)n=cosnθ+isinnθ
and e^(itheta)=costheta+isinthetaeiθ=cosθ+isinθ
Here we have 5e^(15i)=5(cos15+isin15)5e15i=5(cos15+isin15)
:.(5e^(15i))^3=5^3(cos15+isin15)^3
=125(cos45+isin45)