Answer
The power of the complex numbers in the polar form are $5\left[ \cos {{285}^{{}^\circ }}+i\sin {{285}^{{}^\circ }} \right]\ \ \ \text{ and }\ \ 5\left[ \cos {{105}^{{}^\circ }}+i\sin {{105}^{{}^\circ }} \right]\ $.
Work Step by Step
Here $n=2$
$z=25\left( \cos {{210}^{{}^\circ }}+i\sin {{210}^{{}^\circ }} \right)$
Therefore
$\begin{align}
& {{z}_{1}}=\sqrt[2]{25}\left[ \cos \left( \frac{{{210}^{{}^\circ }}+{{360}^{{}^\circ }}}{2} \right)+i\sin \left( \frac{{{210}^{{}^\circ }}+{{360}^{{}^\circ }}}{2} \right) \right]\ \ \ \\
& {{z}_{1}}=5\left[ \cos \left( \frac{{{570}^{{}^\circ }}}{2} \right)+i\sin \left( \frac{{{570}^{{}^\circ }}}{2} \right) \right]\ \ \ \\
\end{align}$ \
Similarly, for the other root,
$\begin{align}
& {{z}_{0}}=\sqrt[2]{25}\left[ \cos \left( \frac{{{210}^{{}^\circ }}+{{360}^{{}^\circ }}\times 0}{2} \right)+i\sin \left( \frac{{{210}^{{}^\circ }}+{{360}^{{}^\circ }}\times 0}{2} \right) \right]\ \ \ \\
& {{z}_{0}}=5\left[ \cos {{105}^{{}^\circ }}+i\sin {{105}^{{}^\circ }} \right]\ \ \ \\
\end{align}$
The square roots of the complex numbers in the polar form is $5\left[ \cos \left( \frac{{{570}^{{}^\circ }}}{2} \right)+i\sin \left( \frac{{{570}^{{}^\circ }}}{2} \right) \right]\ \ \ $ and $5\left[ \cos {{105}^{{}^\circ }}+i\sin {{105}^{{}^\circ }} \right]\ \ \ $
