Solve the quadratic equation $x^2-4x=-2x-1$

$\frac{d}{dx}\left(\sqrt{\frac{x\left(x+2\right)}{\left(2x+1\right)\left(5x+3\right)}}\right)$

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

$\frac{d}{dx}\left(x\arctan\left(x\right)\right)$

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

$\frac{d}{dx}\left(\sech\left(-4x\right)\left(1-\ln\left(\sech\left(-4x\right)\right)\right)\right)$

$\frac{d}{dx}\left(2x^3\tanh\left(\frac{1}{x^2}\right)\right)$

$\frac{d}{dx}\tan\left(x\right)$