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Câu hỏi: Hàm số $f\left( x \right)=\ln \left( {{x}^{2}}-x+2 \right)$ có đạo hàm
A. $f'\left( x \right)=\dfrac{2x-2}{{{x}^{2}}-x+2}$.
B. $f'\left( x \right)=\dfrac{2x-1}{{{x}^{2}}-x+2}$.
C. $f'\left( x \right)=\dfrac{2x-1}{{{\left( {{x}^{2}}-x+2 \right)}^{2}}}$.
D. $f'\left( x \right)=\dfrac{1}{{{x}^{2}}-x+2}$.
Ta có: $f'\left( x \right)=\dfrac{\left( {{x}^{2}}-x+2 \right)'}{{{x}^{2}}-x+2}=\dfrac{2x-1}{{{x}^{2}}-x+2}$.
A. $f'\left( x \right)=\dfrac{2x-2}{{{x}^{2}}-x+2}$.
B. $f'\left( x \right)=\dfrac{2x-1}{{{x}^{2}}-x+2}$.
C. $f'\left( x \right)=\dfrac{2x-1}{{{\left( {{x}^{2}}-x+2 \right)}^{2}}}$.
D. $f'\left( x \right)=\dfrac{1}{{{x}^{2}}-x+2}$.
Ta có: $f'\left( x \right)=\dfrac{\left( {{x}^{2}}-x+2 \right)'}{{{x}^{2}}-x+2}=\dfrac{2x-1}{{{x}^{2}}-x+2}$.
Đáp án B.