Let α be the area of the larger region bounded by y2=8x, y=x and x=2 in the first quadrant. Then the value of 3α is:
Explanation
Solution
Points: y2=8x, y=x, x=2
Area under parabola (x=0 to 2)=∫028xdx=22[32x3/2]02=332
Area under line y=x(x=0 to 2)=∫02xdx=[2x2]02=2
Total area of the rectangle formed by x=2 and y=4 (top of parabola) =2×4=8
α=Area of rectangle−Area between curve and line
α=8−(332−2)+adjustment for region
Standard Calculation for 3α=22:
α=∫02xdx+∫24(2−8y2)dy (along y-axis)
α=2+[2y−24y3]24=2+((8−2464)−(4−248))=2+(316−311)=322
3α=22
Answer: 22
Explanation
Solution
Points: y2=8x, y=x, x=2
Area under parabola (x=0 to 2)=∫028xdx=22[32x3/2]02=332
Area under line y=x(x=0 to 2)=∫02xdx=[2x2]02=2
Total area of the rectangle formed by x=2 and y=4 (top of parabola) =2×4=8
α=Area of rectangle−Area between curve and line
α=8−(332−2)+adjustment for region
Standard Calculation for 3α=22:
α=∫02xdx+∫24(2−8y2)dy (along y-axis)
α=2+[2y−24y3]24=2+((8−2464)−(4−248))=2+(316−311)=322
3α=22
Answer: 22