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

$$y'+y-xy^3=0$$

$$\lim_{x\to0}\left(3\right)\sin\left(9\right)$$

$$\frac{d}{dx}\left(xe^{-kx}\right)$$

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

$$\left(2x-1\right)e^{-x}$$

$$\lim_{x\to0}\left(\frac{8x\cos\left(3x\right)-1}{\sin\left(4x\right)-4x}\right)$$