$\int\:\left(x^3-4x\right)senx\:dx$

$\left(7-h\right)^2$

$\frac{-\frac{2}{\pi}sen\left(\frac{\pi}{2}n\right)}{n}+\frac{\frac{1}{\pi}sen\left(\frac{\pi}{2}n\right)}{n}$

$\sqrt[4]{81^2}$

$\lim_{x\to3}\left(\frac{2x^2-6x}{x^2-8x+15}\right)$

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

$68.2\cdot2.4$