Question

If A = 3 + j1, then A^4 is equal to __________

(a) 3.16 ∠18.4°

(b) 100 ∠73.72°

(c) 100 ∠18.4°

(d) 3.16 ∠73.22°

I had been asked this question in an internship interview.

This question is from Advanced Problems on Network Theory in chapter Network Theory and Complex Circuit Diagram of Network Theory

Answer 1

Correct answer is (b) 100 ∠73.72°

Easy explanation: Given A = 3 + j1

So, 3 + j1 = 10∠18.43°

Or, 3 + j1 = (10)^4 ∠4 X 18.43°

= 100∠73.72°.