$\frac{\tan\left(x\right)}{\sec x-1}$

$\left(x^{-5}\right)^{-2}$

$\left(6\cdot9\right)-\left(2\cdot7\right)+30$

$\frac{5a\sqrt[3]{x}}{3x}$

$\frac{1}{1-\cos\left(x\right)}+\frac{1}{1+cos\left(x\right)}=\frac{2}{sin^2\left(x\right)}$

$15x^4+5x^2y-10y^2$

$\lim_{x\to0}\left(\frac{arcsin\left(3x\right)}{x}\right)$