Question

Express the complex number in trigonometric form.

-5i

Answer 1

@iPwnBunnies

Answer 2

I'm not sure about this, sorry.

Answer 3

@ganeshie8

Answer 4

The trigonometric form looks like this:\[z=r(\cos \theta + isin \theta )\] To find r use this equation:\[r=\sqrt{x ^{2}+y ^{2}}\]Your complex number has an x value of zero.
So r = 5

Since x=0, -5i is completely on the imaginary axis. So the angle is going to be \[3\pi/2\]

So your equation will look like this:\[z=5(\cos 3\pi/2 +i \sin 3\pi/2 )\]