This is the trigonometric form of a complex number where is the modulus and is the angle created on the complex plane.
The modulus of a complex number is the distance from the origin on the complex plane.
Substitute the actual values of and .
Raise to the power of .
Rewrite as .
Pull terms out from under the radical, assuming positive real numbers.
The angle of the point on the complex plane is the inverse tangent of the complex portion over the real portion.
Since the argument is undefined and is negative, the angle of the point on the complex plane is .
Substitute the values of and .
Convert to Trigonometric Form -8i