Question

Express the complex number in trigonometric form 3i

Answer 1

Choices:
3(cos 180° + i sin 180°)

3(cos 270° + i sin 270°)

3(cos 90° + i sin 90°)

3(cos 0° + i sin 0°)

Answer 2

which choices can you eliminate, any?

Answer 3

i got
z = 3i
r=3
theta=taninverse(3/0)=undefine
as we know tan theta is undefine at 90 and 270....check through qustion ..their is + sign with imag part....its mean angle is 90
so we write it as
3(cos90 + isin90) is that right?

Answer 4

well, the does seem correct to me