KCET · Maths · Definite Integration
If \(\int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x A \log |x-1| B\) \(\log |x-2|+C \log |x-3|+C\), then the values of \(A, B\) and \(C\) are respectively
- A \(5,-7,-5\)
- B \(2,-7,-5\)
- C \(5,-7,5\)
- D \(2,-7,5\)
Answer & Solution
Correct Answer
(D) \(2,-7,5\)
Step-by-step Solution
Detailed explanation
We have,
\(\int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x\)
Let \(\frac{3 x+1}{(x-1)(x-2)(x-3)}=\frac{A}{x-1}+\frac{B}{x-2}+\frac{C}{x-3}\)
\(\Rightarrow \quad(3 x+1)=A(x-2)(x-3)+B(x-1)(x-3)\)
\(+C(x-1)(x-2)\)
Put \(x-1=0\)
\(\Rightarrow \quad x=1\)
Then, \(3 \times 1+1=A(-1)(-2)\)
\(\Rightarrow \quad 4=2 A\)
\(\Rightarrow \quad A=2\)
Put \(\quad x-2=0\)
\(\Rightarrow \quad x=2\)
Then, \(7=B(2-1)(2-3)\)
\(\Rightarrow \quad 7=B(1)(-1)\)
\(\Rightarrow \quad B=-7\)
And put \(x-3=0\)
\(\Rightarrow \quad x=3\)
Then, \(10=C(3-1)(3-2)\)
\(\Rightarrow \quad 10=C(2)(1)\)
\(\Rightarrow \quad C=5\)
\(\therefore \quad \frac{3 x+1}{(x-1)(x-2)(x-3)}=\frac{2}{x-1}-\frac{7}{x-2}+\frac{5}{x-3}\)
\(\therefore \quad \int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x\)
\(\quad=\int \frac{2}{x-1} d x-\int \frac{7}{x-2} d x+\int \frac{5}{x-3} d x\)
\(\Rightarrow \quad \int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x\)
\(=2 \log |x-1|-7 \log |x-2|+5 \log |x-3|+C\)
\(=A \log |x-1|+B \log |x-2|+C \log |x-3|+C\)
\((\) Given \()\)
\(\Rightarrow A=2, B=-7, C=5\)
\(\int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x\)
Let \(\frac{3 x+1}{(x-1)(x-2)(x-3)}=\frac{A}{x-1}+\frac{B}{x-2}+\frac{C}{x-3}\)
\(\Rightarrow \quad(3 x+1)=A(x-2)(x-3)+B(x-1)(x-3)\)
\(+C(x-1)(x-2)\)
Put \(x-1=0\)
\(\Rightarrow \quad x=1\)
Then, \(3 \times 1+1=A(-1)(-2)\)
\(\Rightarrow \quad 4=2 A\)
\(\Rightarrow \quad A=2\)
Put \(\quad x-2=0\)
\(\Rightarrow \quad x=2\)
Then, \(7=B(2-1)(2-3)\)
\(\Rightarrow \quad 7=B(1)(-1)\)
\(\Rightarrow \quad B=-7\)
And put \(x-3=0\)
\(\Rightarrow \quad x=3\)
Then, \(10=C(3-1)(3-2)\)
\(\Rightarrow \quad 10=C(2)(1)\)
\(\Rightarrow \quad C=5\)
\(\therefore \quad \frac{3 x+1}{(x-1)(x-2)(x-3)}=\frac{2}{x-1}-\frac{7}{x-2}+\frac{5}{x-3}\)
\(\therefore \quad \int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x\)
\(\quad=\int \frac{2}{x-1} d x-\int \frac{7}{x-2} d x+\int \frac{5}{x-3} d x\)
\(\Rightarrow \quad \int \frac{3 x+1}{(x-1)(x-2)(x-3)} d x\)
\(=2 \log |x-1|-7 \log |x-2|+5 \log |x-3|+C\)
\(=A \log |x-1|+B \log |x-2|+C \log |x-3|+C\)
\((\) Given \()\)
\(\Rightarrow A=2, B=-7, C=5\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- \(n\)th term of the series \(1+\frac{3}{7}+\frac{5}{7^2}+\frac{1}{7^2}+\ldots\) isKCET 2023 Easy
- The area bounded by the curve \(x=4-y^{2}\) and the \(Y\)-axis isKCET 2007 Hard
- Integrating factor of the differential equation \((1 + x^2)\dfrac{dy}{dx} + xy = 1\) isKCET 2026 Easy
- \( \int x^{3} \sin 3 x d x= \)KCET 2019 Hard
- The mean deviation about the mean for the date \(4,7,8,9,10,12,13,17\) isKCET 2025 Medium
- The angle between the pair of lines \(x^{2}+2 x y-y^{2}=0\) isKCET 2009 Easy
More PYQs from KCET
- The branch of biology that deals with study of fossil animals is known asKCET 2013 Medium
- Tertiary alkyl halide is practically to substitution by \( S_{N} 2 \) mechanism because ofKCET 2018 Easy
- If a germ cell in a female gonad and a germ cell in a male gonad begin undergoing meiosis simulataneously, what will be the ratio of ova and sperms produced?KCET 2005 Easy
- A student observed the slide of mitosis under the micro-scope and observed that the chromosomes were placed at the opposite poles. Which stage was the student observing?KCET 2025 Easy
- If the parametric equation of curve is given by \(x=\cos \theta+\log \tan \frac{\theta}{2}\) and \(y=\sin \theta\), then the points for which \(\frac{d y}{d x}=0\) are given byKCET 2021 Medium
- Which one of the following does not involve coagulation?KCET 2010 Easy