$\int ycos\left(y\right)dy$

$\int_3^{\infty}\left(\frac{7}{\left(x-2\right)^2}\right)dx$

$\int_{-1}^{1}x^{2}\sqrt{1-x^{2}}dx$

$logx\:+\:log\left(x-4\right)=2$

$\lim_{x\to\infty}\left(\frac{-ln\left(x\right)-1}{x}\right)$

$\left(-80\right)\cdot\left(+20\right)$

$\frac{1-\tan^2x}{1+\tan^2x}=1-\sin^2x$