- #1
Razberryz
- 22
- 0
Homework Statement
Express the complex number (−3 +4i)3 in the form a + bi
Homework Equations
z = r(cos(θ) + isin(θ))
The Attempt at a Solution
z = -3 + 4i
z3 = r3(cos(3θ) + isin(3θ))
r = sqrt ((-3)2 + 42)
= 5
θ = arcsin(4/5) = 0.9273
∴ z3 = 53(cos(3⋅0.9273) + isin(3⋅0.9273))
a = -117
b = 44
Don't see what I did wrong, would appreciate any help.