If the area of the region \(x, y) : 1 - 2x leq y leq 4 - x^2, x geq 0, y geq 0\ is fracalphabeta, alpha, beta, in N, gcd(alpha, beta) = 1, then the value of (alpha + beta) is :

Solution & Explanation

### Related Formula textArea = int_x_1^x_2 (f(x) - g(x)) dx textArea of Parabola piece: int_0^2 (4-x^2) dx ### Core Logic
Area under curve diagram for Q11 - JEE Main 2026 Evening
Area under curve diagram for Q11 - JEE Main 2026 Evening
The region is bounded above by y = 4 - x^2, below by y = 1 - 2x, and constrained to x geq 0, y geq 0. The parabola intersects the x-axis at x=2 (since 4-x^2=0, xgeq 0). The line intersects the x-axis at x=frac12 (since 1-2x=0) and y-axis at y=1. The required area is the area under the parabola in the first quadrant minus the small triangular region bounded by y = 1-2x, x=0, y=0. ### Step 1: Calculate the Area textTotal area under parabola in 1st quadrant = int_0^2 (4 - x^2) dx = left[ 4x - fracx^33 right]_0^2 = 8 - frac83 = frac163 Area of the small right triangle formed by the line y=1-2x in the first quadrant: Vertices are (0,0), (1/2,0), (0,1). textArea of triangle = frac12 times textbase times textheight = frac12 times frac12 times 1 = frac14 ### Step 2: Subtraction and Format Match textRequired Area = frac163 - frac14 = frac64 - 312 = frac6112 Here, alpha = 61, beta = 12. Check gcd(61, 12) = 1. This matches. So, alpha + beta = 61 + 12 = 73. ### Pattern Recognition For areas defined by y geq g(x) when g(x) forms a simple geometric shape (like a line), subtract the geometric area directly rather than splitting the integral algebraically. It eliminates integration errors. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Application of Integrals

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