Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202325 JanuaryEvening Shift
Exam
JEE Main
Year
2023
Date
25 January
Shift
Evening Shift
Subject
Mathematics
Chapter
Definite Integration

JEE Main 2023 · 25 January · Evening Shift · Mathematics · Definite Integration

If ∫ _ (1)/(3) ^ 3 | _ e x|dx = (m)/(n) _ e ( n ^ 2 e ) , where m...

If ∫133∣log⁡ex∣dx=mnlog⁡e(n2e){∫}_{\dfrac{1}{3}}^{3}\left|\log_{e}x\right|dx = \dfrac{m}{n}\log_{e}\left(\dfrac{{n}^{2}}{e}\right), where mm and nn are coprime natural numbers, then m2+n2−5{m}^{2} + {n}^{2} - 5 is equal to _____ .

Correct answer

0

Step-by-step solution

Let

I=∫133∣ln⁡x∣dxI = {∫}_{\dfrac{1}{3}}^{3}\left|\ln x\right|dx

⇒I=∫131∣ln⁡x∣dx+∫13∣ln⁡x∣dx⇒ I = {∫}_{\dfrac{1}{3}}^{1}\left|\ln x\right|dx + {∫}_{1}^{3}\left|\ln x\right|dx

⇒I=−∫131lnxdx+∫13lnxdx⇒ I = - {∫}_{\dfrac{1}{3}}^{1}lnxdx + {∫}_{1}^{3}lnxdx

Since, ln⁡x<0forx∈(0,1)\ln x < 0forx \in \left(0, 1\right).

⇒I=−[xlnx−x]131+[xlnx−x]13⇒ I = - {\left[xlnx - x\right]}_{\dfrac{1}{3}}^{1} + {\left[xlnx - x\right]}_{1}^{3}

⇒I=−[(0−1)−(−13ln⁡3−13)]+[3ln⁡3−3−(0−1)]⇒ I = - \left[\left(0 - 1\right) - \left(- \dfrac{1}{3}\ln 3 - \dfrac{1}{3}\right)\right] + \left[3\ln 3 - 3 - \left(0 - 1\right)\right]

⇒I=23−13ln⁡3+3ln⁡3−2⇒ I = \dfrac{2}{3} - \dfrac{1}{3}\ln 3 + 3\ln 3 - 2

⇒I=83ln⁡3−43⇒ I = \dfrac{8}{3}\ln 3 - \dfrac{4}{3}

⇒I=43(2ln⁡3−1)⇒ I = \dfrac{4}{3}\left(2\ln 3 - 1\right)

⇒I=43(ln32−lne)⇒ I = \dfrac{4}{3}\left(ln{3}^{2} - lne\right)

⇒I=43ln⁡(32e)⇒ I = \dfrac{4}{3}\ln \left(\dfrac{{3}^{2}}{e}\right)

So, m=4,n=3m = 4, n = 3

Hence, m2+n2−5=16+9−5=20{m}^{2} + {n}^{2} - 5 = 16 + 9 - 5 = 20

Practice Definite Integration on Quantrex Academy →

More from Definite Integration

The value of the definite integral ∫_ 0 ^ 2 1 3^ (x+3)/(2) \, dx is JEE Advanced 2026The value of the integral ∫_ 0 ^ 2 x(x^2+x+1) ( x+1 )( x^4+x^2+1 ) \, dx is equal to: JEE Main 2026If ∫_ π/6 ^ π/4 ( (x-(π)/(3)) (x+(π)/(3))+1)dx = α _e( 3 -1) , then 9α^2 is equal to… JEE Main 2026Let A = bmatrix 1 & 3 & -1 2 & 1 & α 0 & 1 & -1 bmatrix be a singular matrix. Let f(x) =… JEE Main 2026Let f: ℝ arrow ℝ be such that f(xy) = f(x)f(y) , for all x, y ∈ ℝ and f(0) ≠ 0 . Let g… JEE Main 2026The value of the integral ∫ _ -1 ^ 1 ((x^3 + |x| + 1)/(x^2 + 2|x| + 1)) dx is equal to : JEE Main 2026The value of the integral ∫_ -π/4 ^ π/4 ( 32 ^4 x 1 + e^ x )dx is: JEE Main 2026Let (2^ 1-a + 2^ 1+a ) , f(a) , (3^a + 3^ -a ) be in A.P. and α be the minimum value of… JEE Main 2026Let f: [1, ∞) arrow R be a differentiable function defined as f(x) = ∫_1^x f(t)\,dt +… JEE Main 2026The value of the integral ∫_0^∞ ( _e(x))/(x^2 + 4)\,dx is: JEE Main 2026The value of the integral ∫_ π/6 ^ π/3 ((4 - ^2 x)/( ^4 x)) dx is: JEE Main 2026The integral ∫_ 0 ^ 1 ^ -1 (1+x+x^2)dx is equal to: JEE Main 2026Let f be a twice differentiable function such that f(x)=∫_ 0 ^ x (t-x)dt-∫_ 0 ^ x f(t)… JEE Main 2026Let ∫_ -2 ^ 2 (| x| + [x x])\,dx = 2(3 - 2) + β , where [·] is the greatest integer… JEE Main 2026The value of ∫_0^ 20π ( ^4 x + ^4 x) \, dx is equal to: JEE Main 2026Let [·] denote the greatest integer function. Then the value of ∫_0^3 ( e^x + e^ -x [x]!… JEE Main 2026 Full Definite Integration list Definite Integration JEE Maths PYQsJEE Mathematics PYQs All JEE Main PYQs