Calculus
posted by Kelly .
I have a problem about complex number.
Let z=7e^(7*pi*i/4) .
Write z, z^4, z^7, z^(2) in the form a + b i
I have no idea how to do it. Any hints will be appreciated.

z=7e^(7*pi*i/4)
z^4 = 7^4 e^(7*pi*i)
And then you use that
e^(i theta) = cos(theta) + i sin(theta)