## Book: RD Sharma - Mathematics (Volume 2)

### Chapter: 21. Areas of Bounded Regions

#### Subject: Maths - Class 12th

##### Q. No. 8 of Exercise 21.1

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8
##### Find the area under the curve above x - axis from x = 0 to x = 2. Draw a sketch of curve also.

Given equations are:

x – axis ...... (1)

x = 0 ...... (2)

x = 2 ...... (3)

And ...... (4)

equation (4) represents a half parabola with vertex at and passing through (2,0) on x - axis, equation (3) represents a line parallel to y - axis at a distance of 2 units and equation (2) represents y - axis.

A rough sketch is given as below: -

We have to find the area of shaded region.

Required area

(the area can be found by taking a small slice in each region of width Δx, then the area of that sliced part will be yΔx as it is a rectangle and then integrating it to get the area of the whole region)

(As x is between (0,2) and the value of y varies)

(as )

Substitute

So the above equation becomes,

On integrating we get,

On applying the limits we get,

Hence the area under the curve above x - axis from x = 0 to x = 2 is equal to square units.

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