Sketch the region common to the circle x2+y2=16 and the parabola x2=6y. Also, find the area of the region, using integration.

Given the boundaries of the area to be found are,


• the circle, x2 + y2 = 16 ---(1)


• the parabola, x2 = 6y ---- (2)


From the equation, of the first circle, x2 + y2 = 16


• the vertex at (0,0) i.e. the origin


• the radius is 4 unit.


From the equation, parabola, x2 = 6y


• the vertex at (0,0) i.e. the origin


• Symmetric about the y-axis, as it has the even power of x.


Now to find the point of intersection of (1) and (2), substitute x2 = 6y in (1)


6y + y2 = 16


y2 + 6y - 16= 0



y = 2 (or) y = -8


as x cannot be imaginary, y = 2


Substituting x in (2), we get x = ± 2√3


So the two points, A and B where (1) and (2) meet are A = (2√3,2) and B = (-2√3,2)



As x and y have even powers for both the circle and parabola, they will be symmetrical about the x-axis and y-axis.


Consider the circle, x2 + y2 = 16, can be re-written as



----- (3)


Consider the parabola, x2 = 6y, can be re-written as


----- (4)


Let us drop a perpendicular from A on to x-axis. The base of the perpendicular is D = (2√ 3, 0)


Now, the area to be found will be the area is


Area of the required region = Area of OACBO.


Area of OABCO= Area of OCAO+ Area of OCBO


[area of OCBO= area of OCAOas the circle is symmetrical about the y-axis]


Area of OACBO= 2 × Area of OCAO---- (5)


Area of OCAO= Area of OCAD - Area of OADO


Area of OCAOis




[Using the formula, and ]




[sin-1(1) = 90° and ]



The Area of OCAOsq. units


Now substituting the area of OCAOin equation (5)


Area of OACBO= 2 × Area of OCAO



Area of the required region is sq. units.


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