$$\cos^2x-\sec^2x$$

$$\left(0\right)\left(-1\right)+\left(-1\right)\left(3\right)+\left(-2\right)\left(2\right)$$

$$\frac{3\sin\left(x\right)}{10\cos\left(x\right)}$$

$$3x^5\left(x^3-5x\right)$$

$$\lim_{x\to0}\left(\frac{\sqrt{x+b}-\sqrt{b}}{x}\right)$$

$$16\cos^2\left(x\right)+14\cos\left(x\right)+3=0$$

$$-\left[-3x^2+\left(-x-\left\{2y-3\right\}\right)\right]+\left\{-\left(2x^2-y\right)+\left(-x-3\right)-2\left(x+y\right)\right\}$$