Find the area of the region bounded by the curve y2 = 2x and x2 + y2 = 4x

y2 = 2x is a parabola


In y2 = 2x parabola it is not defined for negative values of x hence the parabola will be to the right of Y-axis passing through (0, 0)


x2 + y2 = 4x is equation of circle


The general equation of circle is given by x2 + y2 + 2gx + 2fy + c = 0


Centre of circle is (-g, -f) and radius is


In x2 + y2 – 4x = 0, 2g = -4 g = -2 and f = c = 0


Hence center is (-(-2), 0) that is (2, 0) and radius is which is 2


Hence plot the circle and parabola roughly and to mark the intersection points solve the parabola equation and circle equation simultaneously


Put y2 = 2x in x2 + y2 = 4x


x2 + 2x = 4x


x2 – 2x = 0


x(x – 2) = 0


x = 0 and x = 2


Put x = 2 in y2 = 2x


y2 = 2(2)


y = ±2


Hence the circle and parabola intersects at (0, 0), (2, 2) and (2, -2)



By integrating we will get the area only in the 1st quadrant but given parabola and circle are symmetric about X-axis hence area above and below X-axis will be equal


Hence area of shaded region will be twice the area we will get by integration in 1st quadrant …(a)


Observe that


area of shaded in 1st quadrant = area under circle – area under parabola …(i)



Let us find area under circle


x2 + y2 = 4x


y2 = 4x – x2







Integrate from 0 to 2



Using






Now let us find area under parabola


y2 = 2x


y = √2√x


Integrate from 0 to 2










Using (i)


area of shaded in 1st quadrant = unit2


Using (a)


The area required of shaded region = unit2


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