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4 votes
Express the complex number in trigonometric form: -4i

I think the answer is 4(cos 180 + i sin 180)

2 Answers

5 votes

Answer:

4(cos 270° + i sin 270°)

Explanation:

User Denis Barushev
by
8.4k points
2 votes
Since the sin term is imaginary and cos is real, you need an angle that makes cos=0 and sin -1. This is 270 degrees. So
-4i=4(cos(270)+isin(270))
User SynCap
by
8.5k points

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