Question

The area bounded by the curves $$y = \sqrt x ,\,2y + 3 = x$$    and $$x$$-axis in the 1st quadrant is-

A. $$9$$
B. $$\frac{{27}}{4}$$
C. $$36$$
D. $$18$$  
Answer :   $$18$$
Solution :
Given equation of the curves are for $$y = \sqrt x $$   and $$x = 2y + 3$$   in the first quadrant.
On solving both the equation for $$y$$, we get
$$\eqalign{ & y = \sqrt {2y + 3} \cr & \Rightarrow {y^2} = 2y + 3 \cr & \Rightarrow {y^2} - 2y - 3 = 0 \cr & \Rightarrow {y^2} - 3y + y - 3 = 0 \cr & \Rightarrow y\left( {y - 3} \right) + 1\left( {y - 3} \right) = 0 \cr & \Rightarrow \left( {y + 1} \right)\left( {y - 3} \right) = 0 \cr & \Rightarrow y = - 1,\,\,3 \cr} $$
∴ Required area of shaded region,
$$\eqalign{ & A = \int_0^3 {\left( {2y + 3 - {y^2}} \right)dy} = \left[ {\frac{{2{y^2}}}{2} + 3y - \frac{{{y^3}}}{3}} \right]_0^3 \cr & = \left[ {\frac{{18}}{2} + 9 - 9 - 0} \right] \cr & = 9\,{\text{sq}}{\text{. units}} \cr} $$

Releted MCQ Question on
Calculus >> Application of Integration

Releted Question 1

The area bounded by the curves $$y = f\left( x \right),$$   the $$x$$-axis and the ordinates $$x = 1$$  and $$x = b$$  is $$\left( {b - 1} \right)\sin \left( {3b + 4} \right).$$     Then $$f\left( x \right)$$  is-

A. $$\left( {x - 1} \right)\cos \left( {3x + 4} \right)$$
B. $$\sin \,\left( {3x + 4} \right)$$
C. $$\sin \,\left( {3x + 4} \right) + 3\left( {x - 1} \right)\cos \left( {3x + 4} \right)$$
D. none of these
Releted Question 2

The area bounded by the curves $$y = \left| x \right| - 1$$   and $$y = - \left| x \right| + 1$$   is-

A. $$1$$
B. $$2$$
C. $$2\sqrt 2 $$
D. $$4$$
Releted Question 3

The area bounded by the curves $$y = \sqrt x ,\,2y + 3 = x$$    and $$x$$-axis in the 1st quadrant is-

A. $$9$$
B. $$\frac{{27}}{4}$$
C. $$36$$
D. $$18$$
Releted Question 4

The area enclosed between the curves $$y = a{x^2}$$   and $$x = a{y^2}\left( {a > 0} \right)$$    is 1 sq. unit, then the value of $$a$$ is-

A. $$\frac{1}{{\sqrt 3 }}$$
B. $$\frac{1}{2}$$
C. $$1$$
D. $$\frac{1}{3}$$

Practice More Releted MCQ Question on
Application of Integration


Practice More MCQ Question on Maths Section