Question

Euler’s identity e^jθ is expanded as _____

(a) cos θ + j sin θ

(b) cos θ – j sin θ

(c) cos θ + j sin 2θ

(d) cos⁡ 2θ+j sinθ

This question was posed to me by my college professor while I was bunking the class.

I'd like to ask this question from Elementary Signals topic in division Signals and Systems Basics of Signals and Systems

Answer 1

Correct option is (a) cos θ + j sin θ

To explain: The complex exponential e^jθ is expanded as cos θ + j sin θ and is called Euler’s identity with cos θ as real part sin θ as imaginary part.