$\frac{1}{sec-tan}$

$\frac{x^3-x\:+1}{x^2+1}$

$\frac{cos\left(x\right)}{1-sin\left(x\right)}-\frac{1+sin\left(x\right)}{cos\left(x\right)}=0$

$y\frac{dy}{dx}-2e$

$4ab+13bc$

$\int m\left(\sqrt{m^2+2}\right)dx$

$\left(-\frac{7}{5}\right)^9.\left(-\frac{7}{5}\right)^{15}$