$$\left(4a+7j\right)\left(4a-7j\right)$$

$$\left(\cot^2a+1\right)\sin x$$

$$\frac{8x^3-50x^2+18x-18}{4x+3}$$

$$\frac{1}{x+2}>1$$

$$\lim_{x\to0}\left(x^{-\frac{20}{\ln\left(x\right)}}\right)$$

$$\left(3x^4-3x^2\right)x\:\left(x^2+3\right)$$

$$\frac{d}{dx}\frac{\left(\left(3x+2\right)e^{2x}\right)}{\left(2x-1\right)^2}$$