Solution
Related Formula
Area = ∫x₁x₂ (f(x) - g(x)) dx Area of Parabola piece: ∫₀² (4-x²) dxCore Logic
Step 1: Calculate the Area
Total area under parabola in 1st quadrant = ∫₀² (4 - x²) dx = [ 4x - (x³)/(3) ]₀² = 8 - (8)/(3) = (16)/(3)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).
Area of triangle = (1)/(2) × base × height = (1)/(2) × (1)/(2) × 1 = (1)/(4)Step 2: Subtraction and Format Match
Required Area = (16)/(3) - (1)/(4) = (64 - 3)/(12) = (61)/(12)Here, α = 61, β = 12. Check (61, 12) = 1. This matches. So, α + β = 61 + 12 = 73.
Pattern Recognition
For areas defined by y ≥ 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.
Chapter Mix
Class 12 Maths: Application of Integrals