$$\lim_{x\to\frac{\pi}{2}}\left(1+2\cos\left(x\right)\right)^{\frac{1}{cosx}}$$

$$\lim_{x\to2}\left(\frac{x^2+x-6}{x^2-2}\right)$$

$$4\left(x+1\right)+2\left(x-4\right)$$

$$\frac{dy}{dx}y=ln\left(15x\right)+9x$$

$$\left(2x\:+\:3\right)\:\left(2x\:+\:3\right)$$

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

$$log\left(x\right)=1,2$$