Question

Express the complex number in trigonometric form.

-5i

Answer 1

you need two numbers, \(r\) and \(\theta\)
\(r\) is the absolute value of \(-5i\) which should be pretty obvious
is it clear what it is?

Answer 2

5?

Answer 3

yeah 5

Answer 4

you also need the angle \(\theta\)

Answer 5

is it clear what that angle is?

Answer 6

the black part would be tha anagle??

Answer 7

yeah bad picture but you get the idea
are you working with degrees or radians?

Answer 8

degrees

Answer 9

ok then you have a couple choices
you could say \(-90\) degrees, or if you want to go around the other way you could say \(270\) degrees

Answer 10

5(cos 270° + i sin 270°)?

Answer 11

then you are done right?
yup

Answer 12

yes thank you ♥