3.- Derivator - Tangentlinjer och derivatans definition (Envariabelanalys M)

$f'(x)=\lim_{h \to 0}\frac{ 2x^2+h^2+2hx+2\cdot 2x+2h+2}{h}$

$f'(x)=\lim_{h \to 0}\frac{ h^2-2hx-2h}{h}$

$f'(x)=\lim_{h \to 0}( h^2+2hx+2h)$

$f'(x)=\lim_{h \to 0}\frac{ h^2+2hx+2h}{h}$