Question

Express the complex number in trigonometric form.

2i

Answer 1

from the picture you see that \(\theta=\frac{\pi}{2}\) and \(|2i|=2\) so it is
\[2\left(\cos(\frac{\pi}{2})+i\sin(\frac{\pi}{2})\right)\]

Answer 2

the check is easy, since \(\cos(\frac{\pi}{2})=0\) and \(\sin(\frac{\pi}{2})=1\) you get
\(2i=2(0+i)=2i\)

Answer 3

Okay so the degree of cos and isin would be 90