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

$\frac{2}{x+3}-\frac{3}{x+2}$

$\lim_{x\to\infty}\left(1+\frac{1}{5n}\right)$

$\lim_{x\to0}\left(\frac{1-\cos\:\left(x\right)^2}{4x}\right)$

$\frac{tan\left(x\right)}{sin\left(2x\right)}=\:\frac{1}{2}\left(\frac{1}{sin^2x}\right)$

$\frac{1}{cot^2x}=sec^2x-1$

$\int\frac{x+2}{\left(2x^2.\right)}dx$