Practicing Success
If $y=x^{(x \sin x)}$ then $\frac{d y}{d x}=?$ |
$x^{x \cos x}$ $x^{(x \sin x)}[\sin x+\sin \log x]$ $x^{(x \sin x)}[\sin (1+\log x)+x \log x \cos x]$ $x^{(x \sin x)}[\sin \log x+x \log x \cos x]$ |
$x^{(x \sin x)}[\sin (1+\log x)+x \log x \cos x]$ |
$y=x^{x \sin x}$ ....(1) taking logarithm on both sides $\log y=\log x^{x \sin x} \Rightarrow \log y=x \sin x \log x$ (as $\log a^b=b \log a$) differentiating both sides w.r.t (x) $\frac{1}{y} \frac{d y}{d x}=\frac{d}{d x}(x \sin x \log x)$ $\frac{1}{4} \frac{d y}{d x}=x \sin x \frac{d \log x}{d x}+x \log x \frac{d \sin x}{d x}+\sin x \log x \frac{d x}{d x}$ [using product rule for 3 variables (UVW)' = U'(VW) + U(VW)' = U'VW + UV'W + UVW'] so $\frac{d y}{d x}=y\left[\frac{x}{x} \sin x+x \log x \cos x+\sin x \log x\right]$ from (1) $=y(\sin x(1+\log x)+x \log x \cos x)$ $\frac{d y}{d x}=x^{x \sin x} (\sin x(1+\log x)+x \log x \cos x)$ |