$4r+9+r+2p-3$

$\int r\cos\left(\theta\right)dr$

$9x^2-64y^2$

$\frac{dy}{dx}\cos^2\left(x\right)=e^{-y}\left(\sin x\right)$

$\lim_{x\to2.9}\left(\frac{x^2-9}{x-3}\right)$

$\frac{1-\sec\left(x\right)}{1-\cos\left(x\right)}=-\frac{1}{\cos\left(x\right)}$

$\left(140-3x\right)^2$