$$\left(1-x^2\right)\frac{dy}{dx}=\left(1+y^2\right)$$

$$-509-696$$

$$\lim_{x\to0}\left(\frac{3x^2+\tan^2\left(2x\right)}{\sin^2\left(4x\right)}\right)$$

$$10a-a$$

$$12-75u^2$$

$$\lim_{x\to-5}\frac{\left(x+5\right)}{\left|x+5\right|}$$

$$\frac{dy}{dx}e^{sinx}$$