$$\lim_{x\to-5}\left(\frac{2x^2+13x+15}{x+5}\right)$$

$$\lim_{x\to3}\left(\frac{sin2\left(x-3\right)}{x-3}\right)$$

$$\frac{d}{dx}\sqrt{10+tan^2x}$$

$$\log_{90}\left(2\right)+\log_{90}\left(4x^2\right)=1$$

$$\lim_{x\to0}\left(\frac{tan\left(9x\right)-9x}{x^3}\right)$$

$$\frac{\cot\left(\frac{8\pi}{3}\right)+\sec\left(\frac{11\pi}{6}\right)}{\sin\left(-150\right)}$$

$$2\cos\left(2a\right)^2=1+\cos\left(4a\right)$$