$2y\frac{dy}{dx}=-\frac{\sin\left(3x\right)}{\cos\left(3x\right)^3}$

$\lim_{x\to\infty}\left(\frac{x^2+5x-3}{x^2+2x+5}\right)$

$\frac{20}{2x}$

$\int\frac{sec^2\left(2x\right)}{1+3tan^2\left(2x\right)}dx$

$\frac{cot^2\left(x\right)}{1-sin^2\left(x\right)}$

$\int e^{3x}\tan e^{2x}dx$

$121x^2+66x-7$