If $y=\log \left[a^{3 x}\left(\frac{5-x}{x+4}\right)^{\frac{3}{4}}\right]$, then $\frac{d y}{d x}=$
If $y=\log \left[a^{3 x}\left(\frac{5-x}{x+4}\right)^{\frac{3}{4}}\right]$, then $\frac{d y}{d x}=$
- $3+\frac{3}{4(5-x)}-\frac{3}{4(x+4)}$
- $\frac{3}{a}+\frac{3}{4(5-x)}-\frac{3}{4(x+4)}$
- $\frac{3}{\log a}-\frac{3}{4(5-x)}-\frac{3}{4(x+4)}$
- $3 \log a-\frac{3}{4(5-x)}-\frac{3}{4(x+4)}$
Solution
$y=\log \left[a^{3 x}\left(\frac{5-x}{x+4}\right)^{\frac{3}{4}}\right]$
$\begin{aligned} \therefore y &=\log _{a} 3 x+\log \left(\frac{5-x}{x+4}\right)^{\frac{3}{4}} \\ &=3 x \log a+\frac{3}{4} \log (5-x)-\frac{3}{4} \log (x+4) \end{aligned}$
$\therefore \frac{d y}{d x}=3 \log a+\frac{3(-1)}{4(5-x)}-\frac{3}{4(x+4)}$
$=3 \log a-\frac{3}{4(5-x)}-\frac{3}{4(x+4)}$
Asked in: MHT CET 2020 (20 Oct Shift 2)
Practice more Differentiation questions on Aicharya