$\lim_{x\to\infty}\left(\frac{2x^4+5x-6}{2x^2+5}\right)$

$u=\left|\text{\left(x+4\right)^{2 }}-\left(x+3\right)^{2\:}+\left(x+1\right)^2-\left(x+2\right)^2\right|^2$

$\lim_{x\to1}\left(x-1\right)^2.\ln\left(x-1\right)$

$\left(4-x\right)\cdot\left(4+x\right)$

$\int-\frac{1}{2}xcos\left(x\right)dx$

$2x^2-3x+4,\:para\:x=\:2$

$-\left(12-18\right)+\left(-3\right)+\left(-3-15\right)$