Mathematics · Area under the Curves

JEE Main 2026 — 22 January, Morning Shift — Question 3

Let the line x=−1x=-1 divide the area of the region {(x,y):1+x2≤y≤3−x}\left\{(x, y): 1+x^{2} \leq y \leq 3-x\right\} in the ratio m:n,gcd(m,n)=1m: n, g c d (\mathrm{m}, \mathrm{n})=1. Then m+n\mathrm{m}+\mathrm{n} is equal to

  1. Option A:

    2525

  2. Option B:

    2828

  3. Option C:

    2626

  4. Option D:

    2727

    Correct

Answer: D

Step-by-step solution

The region is bounded by y=1+x2y = 1+x^2 (parabola) and y=3−xy = 3-x (line). Find intersection: 1+x2=3−x⇒x2+x−2=0⇒x=−2,11+x^2 = 3-x \Rightarrow x^2+x-2=0 \Rightarrow x=-2,1. So the region is for x∈[−2,1]x \in [-2,1]. Area to the left of x=−1x=-1: A1=∫−2−1[(3−x)−(1+x2)] dx=∫−2−1(2−x−x2) dxA_1 = \int_{-2}^{-1} [(3-x)-(1+x^2)]\,dx = \int_{-2}^{-1} (2-x-x^2)\,dx. Area to the right of x=−1x=-1: A2=∫−11[(3−x)−(1+x2)] dx=∫−11(2−x−x2) dxA_2 = \int_{-1}^{1} [(3-x)-(1+x^2)]\,dx = \int_{-1}^{1} (2-x-x^2)\,dx. Compute A1A_1: [2x−x22−x33]−2−1=(−2−12+13)−(−4−2+83)=76\left[2x - \frac{x^2}{2} - \frac{x^3}{3}\right]_{-2}^{-1} = \left(-2 - \frac{1}{2} + \frac{1}{3}\right) - \left(-4 -2 + \frac{8}{3}\right) = \frac{7}{6}. Compute A2A_2: [2x−x22−x33]−11=(2−12−13)−(−2−12+13)=206=103\left[2x - \frac{x^2}{2} - \frac{x^3}{3}\right]_{-1}^{1} = \left(2 - \frac{1}{2} - \frac{1}{3}\right) - \left(-2 - \frac{1}{2} + \frac{1}{3}\right) = \frac{20}{6} = \frac{10}{3}. Ratio A1:A2=76:103=7:20A_1 : A_2 = \frac{7}{6} : \frac{10}{3} = 7:20. Thus m=7,n=20m=7, n=20 (or vice versa) and m+n=27m+n=27.

Solution figure

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Area under the Curves
Topic
Area under the Curves
Let the line x=-1 divide the area of the region \ (x, y): 1+x 2 leq y… | JEE Main 2026 PYQ with Solution · DhiX AI