Question
Differentiate the functions given in Exercise:
$(\text{x}+3)^2.(\text{x}+4)^3.(\text{x}+5)^4$

Answer

Let $\text{y}=(\text{x}+3)^2.(\text{x}+4)^3.(\text{x}+5)^4\ \dots\text{(i)}$
Taking logs on both sides, we have
$\log\text{y}=2\log(\text{x}+3)+3\log(\text{x}+4)+4\log(\text{x}+5)^4$
$\therefore\ \frac{\text{d}}{\text{dx}}\log\text{y}=2\frac{\text{d}}{\text{dx}}\log(\text{x}+3)+3\frac{\text{d}}{\text{dx}}\log(\text{x}+4)+4\frac{\text{d}}{\text{dx}}\log(\text{x}+5)$
$\Rightarrow\ \frac{1}{\text{y}}\frac{\text{dy}}{\text{dx}}=2\frac{1}{\text{x}+3}\frac{\text{d}}{\text{dx}}(\text{x}+3)+3\frac{1}{\text{x}+4}\frac{\text{d}}{\text{dx}}(\text{x}+4)+4\frac{1}{\text{x}+5}\frac{\text{d}}{\text{dx}}(\text{x}+5)$
$\Rightarrow\ \frac{1}{\text{y}}\frac{\text{dy}}{\text{dx}}=\frac{2}{\text{x}+3}+\frac{3}{\text{x}+4}+\frac{4}{\text{x}+5}$
$\Rightarrow\ \frac{\text{dy}}{\text{dx}}=\text{y}\Big(\frac{2}{\text{x}+3}+\frac{3}{\text{x}+4}+\frac{4}{\text{x}+5}\Big)$
$\Rightarrow\ \frac{\text{dy}}{\text{dx}}=(\text{x}+3)^2(\text{x}+4)^3(\text{x}+5)^4\Big(\frac{2}{\text{x}+3}+\frac{3}{\text{x}+4}+\frac{4}{\text{x}+5}\Big)\ \text{[From eq.(i)]}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Evaluate $I=\int \frac{\log \left(1+\frac{1}{x}\right)}{x(1+x)} d x$
Prove that the given vectors are coplanar:
$\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}},\ 2\hat{\text{i}}+3\hat{\text{j}}-\hat{\text{k}}$ and $-\hat{\text{i}}-2\hat{\text{j}}+2\hat{\text{k}}$
Show that the function given by f(x) = sin x is:
  1. strictly increasing $\bigg(0,\frac{\pi}{2}\bigg),$
  2. strictly decreasing in $\bigg(\frac{\pi}{2},\pi\bigg),$
  3. neither increasing nor decreasing in $(0,\pi).$
If $\vec{\text{a}}\times\vec{\text{b}}=\vec{\text{b}}\times\vec{\text{c}}\neq0,$ then show that $\vec{\text{a}}+\vec{\text{c}}=\text{m}\vec{\text{b}},$ where m is any scalar.
For $A, B$ and $C$ the chances of being selected as the manager of a firm are in the ratio $4:1:2$ respectively. The respective probabilities for them to introduce a radical change in marketing strategy are $0.3, 0.8$ and $0.5.$ If the change does take place, find the probability that it is due to the appointment of $B$ or $C$
Find the equation of a curve passing through the point $(0, 0)$ and whose differential equation is $y' = e^x$ sin x.
In the following, determine the values of constants involved in the definition so that the given function is continuous:
$\text{f(x)}=\begin{cases}\frac{\sin2\text{x}}{5\text{x}},&\text{if }\text{ x}\neq0\\3\text{k},&\text{if }\text{ x}=0\end{cases}$
Find the principal value of the following:
$\sec^{-1}\Big(2\sin\frac{3\pi}{4}\Big)$
Evaluate the following integrals:
$\int\frac{5\text{x}^4+12\text{x}^3+7\text{x}^2}{\text{x}^2+\text{x}}\text{dx}$
Write the set of values of k for which $\text{f}(\text{x})=\text{k}\text{x}-\sin\text{x}$ is increasing on R.