$\int\left(x^2+3x+1\right)e^{-x}dx$

$9\left(a+2d\right)^4-60\left(a+2d\right)^2+100$

$\left(2x-4\right)^4$

$\sen^{4}\theta=\frac{1-\cos^{2}\theta}{\csc^{2}\theta}$

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

$\int\frac{1}{4-2x}dx$

$ylnydx+xdy=0\:,y\left(1\right)=1$