$1.5x-4.2+x-1.9$

$\lim_{x\to0}\left(\frac{\tan\left(x\right)+2}{tan^2x}\right)$

$\frac{2x+1\cdot\:\:\:\:\:5^{x+1}-2^x\cdot\:\:\:\:\:5^x}{8\cdot\:\:5^x+5^x}$

$\sqrt{\frac{c^2-x^2}{c^2+x^2}}$

$\frac{dy}{dx}\left(\sqrt{x+y}=x+y\right)$

$y=\log_{16}\left(x^5\right)$

$2\log\left(x\right)+\log\left(a+b\right)-0.5\log\left(a+bx\right)$