Let the area of the region \(x, y): x^2y + 4 ge 0, x+2y^2ge0, x+4y^2le8, yge0\ be fracmn where m and n are coprime numbers. Then m+n is equal to:

Numerical Answer Type:
Enter a numerical value Answer: 119 to 119 +4 marks

Solution & Explanation

### Related Formula textArea = int_y_1^y_2 (x_textright - x_textleft) dy ### Core Logic We need to find the area bounded by the curves in the first quadrant (since y ge 0). Note that the first inequality x^2y + 4 ge 0 is trivially satisfied for all x, y ge 0. So we focus on bounding x using: Right curve: x = 8 - 4y^2 Left curve: x = -2y^2 However, there might be constraints where these cross or hit the axes. We must inspect intersections. ### Step 1: Finding Intersection Points Where do the left and right parabolas intersect? 8 - 4y^2 = -2y^2 Rightarrow 2y^2 = 8 Rightarrow y^2 = 4 Rightarrow y = 2 (Since y ge 0). Wait, does x have boundaries? Since x can't drop arbitrarily into negative territory if it's restricted by other axes. Let's check x^2y + 4 ge 0. If x = -2y^2, then y must be bounded, but wait - the question limits are actually split into two regions depending on x^2y+4 ge 0? Wait, the first inequality x^2y+4 ge 0 might not be trivial if x is negative. If x = -2y^2, then (-2y^2)^2 y + 4 ge 0 Rightarrow 4y^5 + 4 ge 0, which is true for all y ge 0. Wait, there seems to be a misinterpretation of the first inequality. Let's look closer at the PDF solution boundaries. The integration is broken at y=1. Why? x+2y^2 ge 0 Rightarrow x ge -2y^2. Wait, the solution states another left curve: 2y-4. Is x^2y+4 ge 0 actually x + 2y - 4 ge 0? Yes, OCR shows `x^2y+4` but the solution integrates `(2y-4)`. Thus the original condition is likely x - 2y + 4 ge 0 Rightarrow x ge 2y - 4! Let's assume the left boundary splits between x = -2y^2 and x = 2y - 4. ### Step 2: Region Bounds Intersection of x = -2y^2 and x = 2y - 4: -2y^2 = 2y - 4 Rightarrow y^2 + y - 2 = 0 Rightarrow (y+2)(y-1) = 0 Rightarrow y = 1. Intersection of x = 2y - 4 and x = 8 - 4y^2: 2y - 4 = 8 - 4y^2 Rightarrow 4y^2 + 2y - 12 = 0 Rightarrow 2y^2 + y - 6 = 0 Rightarrow (2y-3)(y+2) = 0 Rightarrow y = 3/2. So the region shifts left boundary at y=1 and closes entirely at y=3/2. ### Step 3: Setting up the Integration Region 1 (from y=0 to y=1): A_1 = int_0^1 ((8 - 4y^2) - (-2y^2)) dy = int_0^1 (8 - 2y^2) dy A_1 = left[ 8y - frac2y^33 right]_0^1 = 8 - frac23 = frac223 Region 2 (from y=1 to y=3/2): A_2 = int_1^3/2 ((8 - 4y^2) - (2y - 4)) dy = int_1^3/2 (12 - 2y - 4y^2) dy A_2 = left[ 12y - y^2 - frac4y^33 right]_1^3/2 A_2 = left( 12left(frac32right) - frac94 - frac43left(frac278right) right) - left( 12 - 1 - frac43 right) A_2 = left( 18 - frac94 - frac92 right) - left( 11 - frac43 right) = left( 18 - frac274 right) - frac293 = frac454 - frac293 = frac135 - 11612 = frac1912 ### Step 4: Final Output Total Area A = A_1 + A_2: A = frac223 + frac1912 = frac88 + 1912 = frac10712 This implies m = 107 and n = 12. Since 107 and 12 are coprime, m + n = 107 + 12 = 119. ### Pattern Recognition When dealing with multiple inequalities bounded by y ge 0, always project horizontally (integrate wrt y) as the bounds natively trace left-to-right distances. Find intersection nodes to partition the integral correctly. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Application of Integrals

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