$\int_0^7\left(-5e^{-5t}\cdot\:cos\left(20\pi t\right)e^{t-7}\right)dt$

$\left(3y^4-1\right)^3$

$\lim_{x\to\frac{3.14}{2}}5cos\left(5x\right)sec\left(9x\right)$

$\lim_{x\to0}\:x^5\:in\:x$

$\int\frac{1}{\left(81+x\right)\sqrt{x}}\:dx$

$e^{-2x}y\frac{dy}{dx}=xy+x$

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