$\frac{30\left(x+y\right)^2-50\left(x+y\right)}{\:2\left(x+y\right)}$

$\left[sec\:\left(a\right)\right]\:\:\left(\sqrt{\csc^2\left(a\right)-1}\right)$

$\left(9x+6\right)\left(81x^2-84x+36\right)$

$\tan\left(\frac{1}{2}x\right)+1=0$

$\int cot^22xcsc^22xdx$

$\csc x\tan x=\frac{1}{\cos x}$

$\lim_{x\to\infty}\frac{\left|x\right|}{x}$