Find the area of the region bounded by the parabola y2=2x+1 and the lines x-y=1.
Given the boundaries of the area O befound are,
• Curve is y2 = 2x +1
• Line x-y = 1
Consider the curve
y2 = 2x +1
This clearly shows, the curve is a parabola with vertex
Consider the curve, y2 = 2x +1 and substitute the line x = y +1 in the curve
y2 = 2(y+1) +1
y2 = 2y +2 +1
y2 = 2y +3
y2 -2y -3 = 0
y = 3 (or) y = -1
substituting y in x-y = 1
x = 4 (or) x = 0
So , the parabola meets the line x-y =1 at 2 points, B (4,3) and C (0,-1)
As per the given boundaries,
• The parabola y2 = 2x +1, with vertex at A(-0.5,0) and symmetric about the x-axis as y has even powers.
• Line x-y = 1
The boundaries of the region to be found are,
•Point A, where the curve y2 = 2x +1 has the extreme end the vertex i.e. A (-0.5,0)
•Point B, where the curve y2 = 2x +1 and the line x-y = 1 meet i.e. B (4,3)
•Point C, where the curve y2 = 2x +1 and the line x-y = 1 meet i.e. B (0,-1) on the negative y
•Point D, where the line x-y = 1 meets the x-axis i.e. D(1,0)
Consider the curve,
y2 = 2x +1
2x = y2 – 1
Consider the line x – y = 1
x = y +1
Area of the required region = Area of ABDC
Area of ABDC = Area above CDB – Area above CAB
[Using the formula ]
The Area of the required region