\(f(x)=x²-x+2\)
\( \lim\limits_{h\to0} \frac{(x+h)^2-(x+h)+2-(x^2-x+2)}{h}\)=\( \lim\limits_{h\to0} \frac{x^2+2hx+h^2-x-h+2-x^2+x-2}{h}\)=
=\( \lim\limits_{h\to0} \frac{2hx+h^2-h}{h}=\lim\limits_{h\to0}2x+h-1=2x-1\)
\(f´(x)=2x-1\)
\(f´(x₀)=2x₀-1\)
\(f´(\frac{4}{3})=2*\frac{4}{3}-1=\frac{5}{3}\)