$\frac{dy}{dx}\left(\frac{csc\left(x\right)}{1+csc\left(x\right)}\right)$

$n^2-25$

$\left(3y-x\right)\left(c-d\right)$

$y=125\left(x^2-6x\right)^2$

$\frac{1}{cot\:a+\:tan\:a}=sin\:a.cos\:a$

$\frac{dy}{dx}\left(\frac{x^3\left(x-7\right)^5}{\left(x^2+2\right)^6}\right)$

$9x^2+18x-54$