Question 972923
Calculating the nth power or the nth root of a complex number in the rectangular form is a complicated, messy business.
Calculate powers and roots of complex numbers in polar form is simple:
For a power: {{{"(r <"}}}{{{theta}}}{{{")"^n=r^n}}}{{{"<"}}}{{{(n*theta)}}} and 
for an nth root: {{{"(r <"}}}{{{theta}}}{{{")"^("1 / n")=r^("1 / n")}}}{{{"<"}}}{{{theta/n=root(n,r)}}}{{{"<"}}}{{{theta/n}}}
 
Transforming between polar and rectangular coordinates is also simple,
so if you are given the rectangular form and need to calculate a power or root,
you can easily transform to polar form, and then calculate the desired power or root in polar form.
If the result must be expressed in rectangular form, you just transform your polar form result to rectangular form.
 
If you have a complex number  {{{a+i*b}}} , or {{{a+j*b}}} (whichever letter you use for {{{sqrt(-1)}}} ),
with real part {{{a}}} , and imaginary part {{{b}}} ,
you can calculate the argument, {{{theta}}} and modulus {{{r}}} from
{{{tan(theta)=b/a}}} and {{{r=sqrt(a^2+b^2)}}} .
If you know the argument, {{{theta}}} and modulus {{{r}}} of a complex number,
you can calculate its real part {{{a}}} , and imaginary part {{{b}}} as
{{{a=r*cos(theta)}}} and {{{a=r*cos(theta)}}}