# How do you express the complex number in trigonometric form # 2(cos 90° + i sin 90°)#?

##### 1 Answer

Jul 30, 2015

In a sense, it's already in trigonometric form. Other common ways to write it, which may be what you are after, are

#### Explanation:

The second form follows from Euler's formula:

The "cis" form of the answer is just another way to write it (

All of this can also be thought of in terms of polar coordinates in the complex plane. The polar coordinates of the complex number