$\lim_{x\to0}\left(\frac{arctan\left(x\right)}{sinx\left(x\right)}\right)$

$\int x^3\left(16+x^2\right)dx$

$\frac{cos^2\left(x\right)-2\cdot cos\left(x\right)+1}{sin\left(x\right)\cdot cos\left(x\right)-sin\left(x\right)}$

$\lim_{x\to0}\left(x.\ln\left(x^2\right)-2x\right)$

$\frac{2}{\sec\:\left(x\right)}=\frac{2-2\sin\:^2\left(x\right)}{\cos\:\left(x\right)}$

$x^2-8+1$

$\int\left(sqrt\left(x+1\right)\right)dx$