$\int cot\left(6x\right)dx$

$\int_0^{\infty}\left(\frac{1}{x^2+1}-\frac{1}{\frac{3}{3x+1}}\right)dx$

$6m^2+23m+21$

$-24+2\left(y-9\right)$

$\left(\sec^4\left(x\right)-\tan^4\left(x\right)\right)-\sec^2\left(x\right)$

$\left(bn-2\right)^2$