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Find the area bounded between the curve y2 = x and the line x = 3. Draw the rough sketch also.    


The equation of parabola is
y2 = x    ...(1)
The equation of line is
x = 3
Also. we know that parabola is symmetric about x-axis.
∴ required area = 2 (area ORP)
equals space 2 integral subscript 0 superscript 3 straight y space dx space equals space 2 space integral subscript 0 superscript 3 space square root of straight x space dx
equals space 2 space integral subscript 0 superscript 3 straight x to the power of 1 half end exponent dx space equals space 2 open square brackets fraction numerator straight x to the power of begin display style 3 over 2 end style end exponent over denominator begin display style 3 over 2 end style end fraction close square brackets subscript 0 superscript 3 space equals space 4 over 3 open square brackets straight x to the power of 3 over 2 end exponent close square brackets subscript 0 superscript 3
equals space 4 over 3 open square brackets 3 to the power of 3 over 2 end exponent minus 0 close square brackets space equals space 4 over 3 cross times square root of 27 space equals space 4 over 3 cross times 3 square root of 3 space equals space 4 square root of 3 space sq. space units.

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Find the area of the region bounded by the curve straight y space equals space 2 square root of 1 minus straight x squared end root and x-axis. Draw a rough sketch..

The given equations are
straight y space equals 2 square root of 1 minus straight x squared end root ...(1)
(In the first quadrant)
and y = 0    ...(2)
[∴ x-axis has equation y = 0]
From (1) and (2), we get,
                    0 space equals space 2 square root of 1 minus straight x squared end root space space space space space space space space rightwards double arrow space space space space space square root of 1 minus straight x squared end root space equals space 0
rightwards double arrow space space space 1 minus straight x squared space equals space 0 space space space space space space space space space space space space rightwards double arrow space space straight x squared space equals space 1 space space space space space space space space rightwards double arrow space space space space straight x space equals space minus 1 comma space space 1
Required area OAB = integral subscript 0 superscript 1 straight y space dx space equals space 2 integral subscript 0 superscript 1 square root of 1 minus straight x squared space end root space dx
                           equals space 2 space open square brackets fraction numerator straight x square root of 1 minus straight x squared end root over denominator 2 end fraction plus 1 half sin to the power of negative 1 end exponent straight x close square brackets subscript 0 superscript 1
equals space open square brackets straight x square root of 1 minus straight x squared end root plus sin to the power of negative 1 end exponent straight x close square brackets subscript 0 superscript 1
equals left parenthesis 0 plus sin to the power of negative 1 end exponent 1 right parenthesis space minus space left parenthesis 0 plus sin to the power of negative 1 end exponent 0 right parenthesis space equals space 0 plus straight pi over 2 minus left parenthesis 0 plus 0 right parenthesis space equals space straight pi over 2


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Find the area of the region bounded by the curve  y = x2 and the line y = 4.


The equation of parabola is
y = x2    ...(1)
The equation of line is
                y = 4
This parabola is symmetrical about y-axis
therefore space space space requird space area space POQRP space equals space 2 space left parenthesis area space OQRO right parenthesis
                                           equals space 2 space integral subscript 0 superscript 4 straight x space dy space equals space 2 space integral subscript 0 superscript 4 square root of straight y space dy
equals space 2 integral subscript 0 superscript 4 straight y to the power of 1 half end exponent dy space equals space 2 open square brackets fraction numerator straight y to the power of begin display style 3 over 2 end style end exponent over denominator begin display style 3 over 2 end style end fraction close square brackets subscript 0 superscript 4 space equals space 4 over 3 open square brackets straight y to the power of 3 over 2 end exponent close square brackets subscript 0 superscript 4 space equals space 4 over 3 open square brackets 4 to the power of 3 over 2 end exponent minus 0 close square brackets
space equals space 4 over 3 open square brackets left parenthesis 2 squared right parenthesis to the power of 3 over 2 end exponent minus 0 close square brackets space equals space 4 over 3 cross times 2 cubed space equals space 4 over 3 cross times 8 space equals space 32 over 3 space sq. space units


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Give the rough sketch of the curve y2 = x and the line x = 4 and find the area between the curve and the line.    


The equation of parabola is
y2 = x    ...(1)
The equation of line is x = 4
Also, we know that parabola is symmetric about x-axis
therefore space space space required space area space equals space 2 space left parenthesis area space ORP right parenthesis
                   equals space 2 integral subscript 0 superscript 4 space straight y space dx space equals space 2 space integral subscript 0 superscript 4 square root of straight x space dx space space space space space space space space space space space space space open square brackets because space of space left parenthesis 1 right parenthesis close square brackets
                   equals space 2 space integral subscript 0 superscript 4 straight x to the power of 1 half end exponent dx space equals space 2 open square brackets fraction numerator straight x to the power of begin display style 3 over 2 end style end exponent over denominator begin display style 3 over 2 end style end fraction close square brackets subscript 0 superscript 4 space equals space 4 over 3 open square brackets straight x to the power of 3 over 2 end exponent close square brackets subscript 0 superscript 4
space equals space 4 over 3 open square brackets 4 to the power of 3 over 2 end exponent minus 0 close square brackets space equals space 4 over 3 cross times square root of 64 space equals space 4 over 3 cross times 8 space equals space 32 over 3 space sq space. units.


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Calculate the area bounded by the parabola y2 = 4 a x and its latus rectum.

The equation of parabola is y2 = 4 a x.    ...(1)
Let O be the vertex, S be the focus and LL' be the latus rectum of parabola.
The equation of latus rectum is x = a.
Also, we know that parabola is symmetric about x-axis.
therefore space space space required space area space space equals space 2 space left parenthesis area space OSL right parenthesis
                            equals space 2 integral subscript 0 superscript straight a straight y space dx space equals space 2 space integral subscript 0 superscript straight a 2 square root of straight a space square root of straight x space dx
equals space 2 space.2 square root of straight a integral subscript 0 superscript straight a straight x to the power of 1 half end exponent dx space equals space 4 square root of straight a open square brackets fraction numerator straight x to the power of begin display style 3 over 2 end style end exponent over denominator begin display style 3 over 2 end style end fraction close square brackets subscript 0 superscript straight a
equals space 4 square root of straight a.2 over 3 open square brackets straight x to the power of 3 over 2 end exponent close square brackets subscript 0 superscript straight a space equals space fraction numerator 8 square root of straight a over denominator 3 end fraction space open square brackets straight a to the power of 3 over 2 end exponent minus 0 close square brackets
equals space fraction numerator 8 square root of straight a over denominator 3 end fraction. straight a to the power of 3 over 2 end exponent space equals space 8 over 3 straight a squared space sq. space units.

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