$\lim_{x\to\frac{\pi}{2}}\left(\frac{\ln\left(\tan\left(x\right)\right)}{\sec\left(x\right)}\right)$

$\int\:\frac{\left(3-x\right)}{\left(4-x\right)^6}dx$

$\int\left(\frac{6}{x\sqrt[2]{64x^2-25}}\right)dx$

$\frac{a^2}{a^2-4}-\frac{1}{a-2}$

$\frac{dy}{dx}\left(\ln\left(e^x+1\right)\right)$

$\frac{\left(5\right)}{\left(x-3\right)^3}$

$\lim_{x\to\frac{\pi}{2}}\left(\frac{tg\left(x\right)}{tg\left(5x\right)}\right)$