If the area of the region {(x,y):1−2x≤y≤4−x2,x≥0,y≥0} is βα, α,β∈N, gcd(α,β)=1, then the value of (α+β) is :
(A)73✓ Correct
(B)85
(C)91
(D)67
Answer: (A)
Solution
The region lies below the parabola y=4−x2 (which meets the x-axis at x=2) and above the larger of y=1−2x and y=0, with x≥0. The line y=1−2x stays above the x-axis only for 0≤x≤21. Hence the area is the area under the parabola on [0,2] minus the triangular area under the line on [0,21]: ∫02(4−x2)dx−∫01/2(1−2x)dx=316−41=1261. With α=61,β=12 and gcd(61,12)=1, the value of α+β is 73.
JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Single correct option