$sinx=\frac{tanx}{secx}$

$\ln\left(9^{\frac{2x}{3}}\right)$

$-0.02x^2-0.94x$

$\cos\:\left(x\right)\sin\:\left(x\right)\left(\frac{1}{\cos\:\left(x\right)}+\frac{1}{\sin\:\left(x\right)}\right)$

$\lim_{x\to\infty}\left(\frac{20+3x^2}{x^2+6x+9}\right)$

$\ln\left(\frac{dy}{dx}\right)=y$

$\left(\frac{2}{3}x^3+y^2\right)\left(\frac{2}{3}x^3-3y^2\right)$