$f(x)=\dfrac{x^2-2x-8}{x^2\cdot(x+1)}$

$l(x)=\sqrt[3]{2x^2-8}$

$n(x)=\sqrt[6]{4x^3-20x^2+8x+32}$

$g(x)=\sin(2x+0{,}5\pi)$

$h(x)=\cos\left(\dfrac{x}{\pi}\right)$

$m(x)=\sqrt{\tan(x)}$

$i(x)=\ln\left(x^3+9\right)$

$k(x)=\log_2\left(x^2+3x-3\right)$