A farmer F1 has a land in the shape of a triangle with vertices at P(0,0), Q(1,1) and R(2,0). From this land, a neighbouring farmer F2 takes away the region which lies between the side PQ and a curve of the form y=xn (n > 1). If the area of the region taken away by the farmer F2 is exactly 30% of the area of Δ PQR, then the value of n is_____
Q. A farmer F1 has a land in the shape of a triangle with vertices at P(0,0), Q(1,1) and R(2,0). From this land, a neighbouring farmer F2 takes away the region which lies between the side PQ and a curve of the form y=xn(n>1). If the area of the region taken away by the farmer F2 is exactly 30% of the area of Δ PQR, then the value of n is_____
Calculate Triangle Area: Calculate the area of triangle PQR.The area of a triangle with vertices at (x1,y1),(x2,y2), and (x3,y3) is given by the formula:Area = 21∣x1(y2−y3)+x2(y3−y1)+x3(y1−y2)∣Substitute the given points P(0,0), Q(1,1), and R(2,0) into the formula.Area = 21∣0(1−0)+1(0−0)+2(0−1)∣Area = 21∣0+0−2∣Area = 21∣−2∣Area = 1
Calculate 30%: Calculate 30% of the area of triangle PQR.30% of the area is 0.3 times the area of the triangle.0.3×Area=0.3×1=0.3
Set up Integral: Set up the integral to find the area between PQ and y=xn. The area taken away by farmer F2 is the area under the curve y=xn from x=0 to x=1 minus the area of the triangle formed by the line y=x and the x-axis from x=0 to x=1. The area under the curve is given by the integral from 0 to 1 of F20. The area of the small triangle is F21. So, the area taken away is the integral minus the area of the small triangle.
Calculate Integral: Calculate the integral and set it equal to 30% of the area of triangle PQR.The integral of xn from 0 to 1 is (n+1)1x(n+1) evaluated from 0 to 1.This equals (n+1)1×1(n+1)−(n+1)1×0(n+1)=(n+1)1.The area taken away is (n+1)1−21.Set this equal to 0.3 (from Step 2) and solve for xn0.xn1
Solve for n: Solve the equation for n.n+11−21=0.3Multiply through by 2(n+1) to clear the denominators:2−(n+1)=0.6(n+1)2−n−1=0.6n+0.61−n=0.6n+0.61−0.6=0.6n+n0.4=1.6nn=1.60.4n=41
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