Question

Determine the polar form of the complex number 3 - 2i. Express the angle theta in degrees, where 0 < theta < 360°, and round numerical entries in the answer to two decimal places.

3.61(cos 326.31° – isin 326.31°)
3.61(cos 326.31° + isin 326.31°)

Answer 1

I know this is the answer but which sign? + or - in the second part?

Answer 2

umm no im sorry

Answer 3

@SolomonZelman

Answer 4

It should always be a +, if you're doing it this way. You'll still end up with a 3-2i when you evaluate it, since sin 326.31 is itself negative.

Answer 5

Its always +? Thanks ^^

Answer 6

Yup, as long as you set the angle correctly, it can always be a +. But, since 360-326.31 = 33.79, you could write this same number also as 3.61(cos 33.79 - i sin 33.79). It's up to you which way to write it, but you can always check yourself just by checking that the sign of the real and imaginary parts are both correct.