$\frac{1}{1-sec\:x}+\frac{1}{1+sec\:x}$

$\left(x+y^3\right)+6xy^2y'=0$

$-81+81a^2$

$\frac{1+\tan\left(a\right)}{\sec\left(a\right)}=\cos\left(a\right)+\sin\left(a\right)$

$\frac{d^2}{dt^2}\left(t^{11}\ln\left(t\right)\right)$

$\int5te^{-0.1t\:}dx$

$\int_0^2\left(\frac{1}{27+21\cos\left(x\right)}\right)dx$