a.
\(f'\left(3\right)=\lim\limits_{x\rightarrow3}\dfrac{f\left(x\right)-f\left(3\right)}{x-3}=\lim\limits_{x\rightarrow3}\dfrac{x^2-4x+5-\left(3^2-4.3+5\right)}{x-3}\)
\(=\lim\limits_{x\rightarrow3}\dfrac{x^2-4x+3}{x-3}=\lim\limits_{x\rightarrow3}\dfrac{\left(x-1\right)\left(x-3\right)}{x-3}\)
\(=\lim\limits_{x\rightarrow3}\left(x-1\right)=3-1=2\)
b.
\(f'\left(0\right)=\lim\limits_{x\rightarrow0}\dfrac{f\left(x\right)-f\left(0\right)}{x-0}=\lim\limits_{x\rightarrow0}\dfrac{2x^2+x-1-\left(-1\right)}{x}=\lim\limits_{x\rightarrow0}\dfrac{2x^2+x}{x}\)
\(=\lim\limits_{x\rightarrow0}\dfrac{x\left(2x+1\right)}{x}=\lim\limits_{x\rightarrow0}\left(2x+1\right)\)
\(=2.0+1=1\)
giúp em câu hình với ạ. Làm ơn
