NCERT Solutions for Class 12 Maths Exercise 8.1 Chapter 8 Application of Integrals – FREE PDF Download
Free PDF download of NCERT Solutions for Class 12 Maths Chapter 8 Exercise 8.1 (Ex 8.1) and all chapter exercises at one place prepared by expert teacher as per NCERT (CBSE) books guidelines. Class 12 Maths Chapter 8 Application of Integrals Exercise 8.1 Questions with Solutions to help you to revise complete Syllabus and Score More marks. You can download them in PDF format for free.
NCERT Solutions for Class 12 Maths Chapter 8 Application of Integrals (Ex 8.1) Exercise 8.1
1. Find the area of the region bounded by the curve and the lines
and the
axis.

……….(i)
Required area (shaded region)
= [From eq. (i)]
= =
=
= =
=
sq. units
2. Find the area of the region bounded by
and the
axis in the first quadrant.

……….(i)
Required area (shaded region) bounded by curve
(vertical lines
) and
axis in first quadrant.
= ∣∣∣∫24ydx∣∣∣=∣∣∣∫243x−−√dx∣∣∣|∫24ydx|=|∫243xdx| [From eq. (i)]
= =
= =
= =
sq. units
3. Find the area of the region bounded by
and the
axis in the first quadrant.



Required (shaded) area bounded by curve
(Horizontal lines
) and
axis in first quadrant.
=
= =
=
sq. units
4. Find the area of the region bounded by the ellipse 

Here
From eq. (i),
y=±3416−x2−−−−−−√y=±3416−x2……….(ii)
For arc of ellipse in first quadrant.
Ellipse (i) ia symmetrical about axis,
( On changing
in eq. (i), it remains unchanged)
Ellipse (i) ia symmetrical about axis,
( On changing
in eq. (i), it remains unchanged)
Intersections of ellipse (i) with axis
Putting in eq. (i),
Therefore, Intersections of ellipse (i) with axis are (0, 4) and
.
Intersections of ellipse (i) with axis
Putting in eq. (i),
Therefore, Intersections of ellipse (i) with axis are (0, 3) and
.
Now Area of region bounded by ellipse (i) = Total shaded area
= 4 x Area OAB of ellipse in first quadrant
= [
At end B of arc AB of ellipse;
and at end A of arc AB ;
]
= =
=
= =
= sq. units
5. Find the area of the region bounded by the ellipse 

Here
From eq. (i),
y=±324−x2−−−−−√y=±324−x2……….(ii)
for arc of ellipse in first quadrant.
Ellipse (i) ia symmetrical about axis,
( On changing
in eq. (i), it remains unchanged)
Ellipse (i) ia symmetrical about axis,
( On changing
in eq. (i), it remains unchanged)
Intersections of ellipse (i) with axis
Putting in eq. (i),
Therefore, Intersections of ellipse (i) with axis are (0, 2) and
.
Intersections of ellipse (i) with axis
Putting in eq. (i),
Therefore, Intersections of ellipse (i) with axis are (0, 3) and
.
Now Area of region bounded by ellipse (i) = Total shaded area
= 4 x Area OAB of ellipse in first quadrant
= [
At end B of arc AB of ellipse;
and at end A of arc AB ;
]
= =
=
=
= sq. units
6. Find the area of the region in the first quadrant enclosed by
axis, line
and the circle 
Equation of the circle is ……….(i)
We know that eq. (i) represents a circle whose centre is (0, 0) and radius is 2.
Equation of the given line is
……….(ii)
We know that eq. (ii) being of the form where
represents a straight line passing through the origin and making angle of
with
axis.
Step II. To find values of and
Putting
from eq. (ii) in eq. (i),
Putting in
,
and
Therefore, the two points of intersections of circle (i) and line (ii) are A and D
.
Step III. Now shaded area OAM between segment OA of line (ii) and axis
=
= =
=
=
=
sq. units……….(iii)
Step IV. Now shaded area AMB between are AB of circle and axis.
= =
= From eq. (ii),
= =
= =
=
sq. units……….(iv)
Step V. Required shaded area OAB = Area of OAM + Area of AMB
= sq. units
7. Find the area of the smaller part of the circle
cut off by the line 

……….(ii)
Here Area of smaller part of the circle cut off by the line
= Area of ABMC = 2 x Area of ABM
= =
[From eq. (ii)]
=
=
= 2[0+a22.π2−a2√×a2√−a22sin−112√]2[0+a22.π2−a2×a2−a22sin−112]
= 2[πa24−a2√×a2√−a22.π4]2[πa24−a2×a2−a22.π4]
= 2[πa24−a22−πa28]2[πa24−a22−πa28]
= 2a2[π4−12−π8]2a2[π4−12−π8]
= 2a2[2π−2−π8]2a2[2π−2−π8]
= a24(π−2)=πa24−a22a24(π−2)=πa24−a22
=>a22(π2−1)=>a22(π2−1)sq. units
8. The area between
and
is divided into two equal parts by the line
find the value of 

Now area bounded by parabola (i) and vertical line is divided into two equal parts by the vertical line
Area OAMB = Area AMBDNC
=
=
=
units
9. Find the area of the region bounded by the parabola
and 


To find: Area between the parabola and the ray
for
Here, Limits of integration
Now, for , table of values,
if
if
![]() | 0 | 1 | 2 |
![]() | 0 | 1 | 2 |
![]() | 0 | ![]() | ![]() |
![]() | 0 | 1 | 2 |
Now, Area between parabola and
axis between limits
and
= =
=
………..(i)
And Area of ray and
axis,
= =
=
………..(ii)
Required shaded area in first quadrant = Area between ray
for
and
axis Area between parabola
and
axis in first quadrant
= Area given by eq. (ii) – Area given by eq. (i) = sq. units
Similarly, shaded area in second quadrant = 1616sq. units
Therefore, total area of shaded region in the above figure = 1616+ 1616= 1313sq. units
10. Find the area bounded by the curve x2=4yx2=4y and the line 
Equation of the given curve is
……..(i)
Equation of the given line is
……….(ii)
![]() | 0 | 1 | ![]() |
![]() | 0 | ![]() | 0 |
Step II. Putting from eq. (i) in eq. (ii),
x(x−2)+1(x−2)=0x(x−2)+1(x−2)=0
or
For ,from eq. (i),
(2, 1)
For from eq. (i),
Therefore, the two points of intersection of parabola (i) and line (ii) are C and D (2, 1).
Step III. Area CMOEDN between parabola (i) and axis =
=
= =
=
sq. units……..(iii)
Step IV. Area of trapezium CMND between line (ii) and axis =
=
= =
=
=
= =
sq. units……….(iv)
Required shaded area = Area given by eq. (iv) – Area given by eq. (iii)
= sq. units
11. Find the area of the region bounded by the curve
and the line 


Here required shaded area OAMB = 2 x Area OAM

=



=



12. Choose the correct answer:
Area lying in the first quadrant and bounded by the circle and the lines
and
is
(A)
(B)
(C)
(D)

……….(ii)
Required area = =
=
=
= =
sq. units
Therefore, option (A) is correct.
13. Choose the correct answer:
Area of the region bounded by the curve axis and the line
is:
(A) 2
(B)
(C)
(D)

Required area = Area OAM = = ∣∣∣∫03y24dy∣∣∣|∫03y24dy|
= 14∣∣∣(y33)30∣∣∣14|(y33)03| = sq. units
Therefore, option (B) is correct.