$z=\sqrt{x^2+y^2}$

$\left[csc\left(\frac{\pi}{4}\right)\right]^2+sin\left(\frac{7\pi}{2}\right)$

$\left(x+0.2\right)^2$

$2\left(4\right)^4+7\left(4\right)^3-4\left(4\right)^2-4-1$

$\int\frac{2x-1}{x^2-4x+4}dx$

$\int\left(2x+1\right)^{13}dx$

$\lim_{x\to-\frac{6}{5}}\left(\frac{25x^2-36}{5x+6}\right)$