(-1+i)(-1-i) in polar form
-1+i = (√2,3π/4)
-1-i = (√2,5π/4)
so,
(-1+i)(-1-i) = (√2*√2,3π/4 + 5π/4) = (2,2π) or (2,0)
You can see this since
(-1+i)(-1-i) = (-1)^2 - i^2 = 1+1 = 2
-1-i = (√2,5π/4)
so,
(-1+i)(-1-i) = (√2*√2,3π/4 + 5π/4) = (2,2π) or (2,0)
You can see this since
(-1+i)(-1-i) = (-1)^2 - i^2 = 1+1 = 2