$\lim_{x\to\infty}\left(\frac{x^2}{2^x+1}\right)$

$\int_{-\cos\left(x\right)}^{\sin\left(x\right)}\left(\frac{1}{\sqrt{1-b^2}}\right)db$

$\left(3x^2-4z\right)^2$

$3xsecx^2\left(x^2\right)$

$-65\:\left(-5\right)$

$-101.78+13,76$

$7\left(3\right)-1\left(-8\right)-4\left(1\right)$