Tuesday, May 12, 2009

Question on Parabola and Area Covered by Parabola

A parabola is a geometrical figure which is expressed in terms of cartesian system. In the same problem you will learn how to find area covered by parabolas.

Topic : Parabola and Area covered by two parabola

In the problem area covered will be one among the choice given.

Question : Find the area covered by two parabola y2 = 4ax and x2 = 4ay
(a). 16a2/3
(b). 5a2

Solution :
Choice a is correct
The equations of the given parabolas are
y2 = 4ax -------- (1) and
x2 = 4ay -------- (2)


The vertices of these parabolas are at the origin and their axes are x-axis and y-axis respectively as shown in figure.

















Solving (1) and (2) for x and y, we get
x4
----- = 4ax
16a2
=> x(x3 - 64a3) = 0
=> x = 0, x = 4a
when x = 0, y =0
And when x=4a, y=4a
The points of intersection of two parabolas are (0,0) and (4a,4a).
Therefore required area (common to both the parabolas)
















Choice b is incorrect

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