Find the sum of $n$ terms of the G,P, $x^2,x^4,x^6...........$ in terms of $x$

Question

$\begin{array}{1 1} x^4 \large\frac{1-x^{2n}}{1-x^2} \\ x^2 \large\frac{1-x^{n}}{1-x^2} \\x^2 \large\frac{1-x^{2n}}{1+x^{2n}} \\ x^2 \large\frac{1-x^{2n}}{1-x^2}\end{array}$