Tìm đạo hàm của hàm số \(y = \frac{{\sin x - x\cos x}}{{\cos x + x\sin x}}\)
\(\begin{array}{l}
\Rightarrow y\prime = \frac{{(\cos x - \cos x + x\sin x)(\cos x + x\sin x) - ( - \sin x + \sin x + x\cos x)(\sin x - x\cos x)}}{{{{(\cos x + x\sin x)}^2}}}\\
= \frac{{x\sin x(\cos x + x\sin x) - x\cos x(\sin x - x\cos x)}}{{{{(\cos x + x\sin x)}^2}}}\\
= \frac{{{x^2}\sin 2x + {x^2}\cos 2x}}{{{{(\cos x + x\sin x)}^2}}} = \frac{{{x^2}}}{{{{(\cos x + x\sin x)}^2}}}
\end{array}\)
-- Mod Toán 11
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