- #1

blues1

- 2

- 0

## Homework Statement

if z = -2 + 2i

find r and θ

## The Attempt at a Solution

our teacher told us that when we have z = a + bi

r = sqrt(a^2 + b^2)

and θ = tan^-1(b/a)

so here it's supposed to be r = sqrt(8) and θ = - pi/4

but using wolfram alpha to see if the results are matching I get that

sqrt(8)*e^(i*-pi/4) is 2 - 2i

what am I doing wrong? I guess this has to do with the θ, but since it's always tan^-1(b/a) why am I getting different results?