Question
Evaluate the following intregals:
$\int\frac{1}{\text{x}[6(\log\text{x})^2+7\log\text{x}+2]}\ \text{dx}$

Answer

Let $\text{I}=\int\frac{\text{dx}}{\text{x}[6(\log\text{x})^2+7\log\text{x}+2]}$ $=\int\frac{1}{\text{x}(2\log\text{x}+1)(3\log\text{x}+2)}\text{ dx}$ Now,Let $\frac{1}{\text{x}(2\log\text{x}+1)(3\log\text{x}+2)}=\frac{\text{A}}{\text{x}(2\log\text{x}+1)}+\frac{\text{B}}{\text{x}(3\log\text{x}+2)}$
$\Rightarrow1=\text{A}(3\log\text{x}+2)+\text{B}(2\log\text{x}+1)$ Put $\text{x}=10^{-\frac12{}{}}$ $\Rightarrow1=\frac{1}{2}\text{A}\Rightarrow\text{A}=2$ $-\frac{2}{3}$ Put $\text{x}=10)^{-\frac23}$ $\Rightarrow1=-\frac{1}{3}\text{B}\Rightarrow\text{B}=-3$ $\therefore\text{I}=\int\frac{2\text{dx}}{\text{x}(2\log\text{x}+1)}-\int\frac{3\text{dx}}{\text{x}(3\log\text{x}+2)}$ $=\log|2\log\text{x}+1|-\log|3\log\text{x}+2|\text{C}$ $\therefore\text{I}=\log\Big|\frac{2\log\text{x}+1}{3\log\text{x}+2}\Big|+\text{C}$

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

Find one$-$parameter families of solution curves of the following differential equation: $($or solve the following differential equation$)\frac{\text{dy}}{\text{dx}}+3\text{y}=\text{e}^{\text{mx}}, m$ is given real number.
The volume of spherical balloon being inflated changes at a constant rate. If initially its radius is 3 units and after 3 seconds it is 6 units. Find the radius of balloon after t seconds.
Prove that the diagonals of a rhombus are perpendicular bisectors of each other.
Solve the following systems of linear equations by cramer's rule:
2x - 3y - 4z = 29,
-2x + 5y - z = -15,
3x - y + 5z = -11
Evaluate: $\int\limits^{3/2}_{0} |x \sin \pi \text{ } x| \text{dx}.$
There are two types of fertilisers 'A' and 'B'. 'A' consists of 12% nitrogen and 5% phosphoric acid whereas 'B' consists of 4% nitrogen and 5% phosphoric acid. After testing the soil conditions, farmer finds that he needs at least 12kg of nitrogen and 12kg of phosphoric acid for his crops. If 'A' costs Rs. 10 per kg and 'B' cost Rs. 8 per kg, then graphically determine how much of each type of fertiliser should be used so that nutrient requiremnets are met at a minimum cost.
Find the point on the curve $y^{2 }= 4x$ which is nearest to the point $(2, -8).$
Using vectors, prove that the parallelogram on the same base and between the same parallels are equal in area.
Find the slopes of the tangent and the normal to the following curves at the indicated points:
$\text{x}=\text{a}(\theta-\sin\theta),\text{y}=\text{a}(1-\cos\theta)\text{at}\theta=-\frac{\pi}{2}$
A particle is moving in a straigth line such that its distance at any time t is given by $\text{S}=\frac{\text{t}^{4}}{4}-2\text{t}^{3}+4\text{t}^{2}-7$. Find when its velocity is maximum and acceleration minimum.