Which expression is equivalent to xn−ynxn/2−yn/2\frac{x^n - y^n}{x^{n/2} - y^{n/2}}xn/2−yn/2xn−yn?
xn/2−yn/2x^{n/2} - y^{n/2}xn/2−yn/2
xn/2+yn/2x^{n/2} + y^{n/2}xn/2+yn/2
xn+ynx^n + y^nxn+yn
xn/2yn/2x^{n/2}y^{n/2}xn/2yn/2