Question Details

The area of the region bounded by the curve x² = 4y and the straight line x = 4y – 2 is

Options

A

3/8 sq.units

B

5/8 sq.units

C

7/8 sq.units

D

9/8 sq. units

Correct Answer :

9/8 sq. units

Solution :

The correct option is 9/8 sq. units.

To find the area of the region bounded by the curve x2=4y and the straight line x=4y2, we first need to determine their points of intersection.

From the equation of the line, we can express 4y in terms of x:
4y=x+2

Substitute this expression for 4y into the equation of the parabola x2=4y:
x2=x+2
x2x2=0

Solving this quadratic equation by factoring:
(x2)(x+1)=0

This gives the x-coordinates of the intersection points:
x=2 and x=1

The region is bounded between x=1 and x=2. In this interval, the line lies above the parabola. Thus, the area A is given by the integral:
A=12(ylineyparabola)dx

Expressing both curves in terms of x:
yline=x+24
yparabola=x24

Set up the integral:
A=12(x+24x24)dx
A=1412(2+xx2)dx

Evaluate the integral:
A=14[2x+x22x33]12

Substitute the upper limit (x=2):
Valueupper=2(2)+222233=4+283=683=103

Substitute the lower limit (x=1):
Valuelower=2(1)+(−1)22(−1)33=2+12+13=12+3+26=76

Subtract the lower limit value from the upper limit value:
[2x+x22x33]12=103(76)=206+76=276=92

Now, multiply by the factor 14 outside the integral:
A=14×92=98 sq. units

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