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

$\lim_{x\to0}\left(e^{\frac{7}{x}}-9x\right)^{\frac{x}{2}}$

$\frac{2\tan\left(x\right)}{1+\tan^2\left(x\right)}\cdot\cot\left(2x\right)$

$-3-4\left(3-6\right)-\left(8+5\right)$

$\left(-0.3\right)\cdot\left(-0.3\right)\cdot\left(-0.3\right)$

$\left(x+1\right)^2\left(x-2\right)\left(x+2\right)$

$\left[-36\right]\:x\:100-2$