Let the line x=−1 divide the area of the region {(x,y):1+x2≤y≤3−x} in the ratio m:n,gcd(m,n)=1. Then m+n is equal to
(A)25
(B)28
(C)26
(D)27✓ Correct
Answer: (D)
Solution
The curves y=1+x2 and y=3−x meet where x2+x−2=0, i.e. at x=−2 and x=1, with 3−x≥1+x2 between them. Let g(x)=(3−x)−(1+x2)=2−x−x2 with antiderivative G(x)=2x−2x2−3x3. The part of the area left of x=−1 is G(−1)−G(−2)=67 and the part right of it is G(1)−G(−1)=620. The line x=−1 therefore divides the area in the ratio 7:20, in which gcd(7,20)=1, so m+n=27.
JEE Main · 2026 · 22 Jan 2026 · Shift 1 · Single correct option