It seems to me that @MichaelAlbanese is right. It should be
$ \frac{1+\sqrt{3} i}{1-\sqrt{3} i} $. After removing any complex part from denominator we get
$$
\frac{1+\sqrt{3} i}{1-\sqrt{3} i} = \frac{1+\sqrt{3} i}{1-\sqrt{3} i} \frac{1+\sqrt{3} i}{1+\sqrt{3} i} = \frac{-2 + 2 \sqrt{3} i}{4} = -\frac{1 - \sqrt{3} i}{2}
$$
We can transfer it into polar form, which is $ {e}^{\frac{2}{3} \pi i} $
And now the answer is quite easy to find
$$
{{e}^{\frac{2}{3} \pi i}}^{10} = {e}^{10 \frac{2}{3} \pi i} = {e}^{\frac{20}{3} \pi i} = {e}^{\frac{18 + 2}{3} \pi i} = {e}^{{6 \pi i} + {\frac{2}{3} \pi i}} = {e}^{6 \pi i} {e}^{\frac{2}{3} \pi i} = {e}^{\frac{2}{3} \pi i}
$$
So the final answer is that $ z^{10} = z = -\frac{1 - \sqrt{3} i}{2}$
BTW, if really $ z = \frac{1+\sqrt{3 i}}{1-\sqrt{3 i}} $ you have big troubles because its polar form is something like that:
$$
z = \frac{\sqrt{{\left( \frac{\sqrt{3}}{\sqrt{2}}+1\right) }^{2}+\frac{3}{2}}\,{e}^{i\,\left( \mathrm{atan}\left( \frac{\sqrt{3}}{\sqrt{2}\,\left( \frac{\sqrt{3}}{\sqrt{2}}+1\right) }\right) +\mathrm{atan}\left( \frac{\sqrt{3}}{\sqrt{2}\,\left( 1-\frac{\sqrt{3}}{\sqrt{2}}\right) }\right) +\pi \right) }}{\sqrt{{\left( 1-\frac{\sqrt{3}}{\sqrt{2}}\right) }^{2}+\frac{3}{2}}}
$$
and the answer is
$$
z^{10} = \frac{{\left( {\left( \frac{\sqrt{3}}{\sqrt{2}}+1\right) }^{2}+\frac{3}{2}\right) }^{5}\,{e}^{i\,\left( \mathrm{atan}\left( \frac{\mathrm{sin}\left( 10\,\mathrm{atan}\left( \frac{\sqrt{3}}{\sqrt{2}\,\left( \frac{\sqrt{3}}{\sqrt{2}}+1\right) }\right) \right) }{\mathrm{cos}\left( 10\,\mathrm{atan}\left( \frac{\sqrt{3}}{\sqrt{2}\,\left( \frac{\sqrt{3}}{\sqrt{2}}+1\right) }\right) \right) }\right) -\mathrm{atan}\left( \frac{\mathrm{sin}\left( 10\,\left( -\mathrm{atan}\left( \frac{\sqrt{3}}{\sqrt{2}\,\left( 1-\frac{\sqrt{3}}{\sqrt{2}}\right) }\right) -\pi \right) \right) }{\mathrm{cos}\left( 10\,\left( -\mathrm{atan}\left( \frac{\sqrt{3}}{\sqrt{2}\,\left( 1-\frac{\sqrt{3}}{\sqrt{2}}\right) }\right) -\pi \right) \right) }\right) \right) }}{{\left( {\left( 1-\frac{\sqrt{3}}{\sqrt{2}}\right) }^{2}+\frac{3}{2}\right) }^{5}}
$$
(thanks Maxima…)