Skip to main content
Chapter 10 of 14
NCERT Solutions

Conic Sections

Madhya Pradesh Board · Class 11 · Mathematics

NCERT Solutions for Conic Sections — Madhya Pradesh Board Class 11 Mathematics.

193 questions56 flashcards5 concepts

Interactive on Super Tutor

Studying Conic Sections? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for ncert solutions and more.

1,000+ Class 11 students started this chapter today

70 Questions Solved · 5 Sections

35 worked solutions below. Unlock all 70 free in Super Tutor

EXERCISE 10.1

1centre (0,2)(0, 2) and radius 2Show solution
For a circle with centre (h,k)(h,k) and radius rr, the equation is

(xh)2+(yk)2=r2. (x-h)^2+(y-k)^2=r^2.

Here h=0h=0, k=2k=2, and r=2r=2. So,

x2+(y2)2=22=4.x^2+(y-2)^2=2^2=4.

Not sure why a step works? check your working in Super Tutor

2centre (2,3)(-2, 3) and radius 4Show solution
Using the standard form of a circle,

(xh)2+(yk)2=r2, (x-h)^2+(y-k)^2=r^2,

with centre (h,k)=(2,3)(h,k)=(-2,3) and radius r=4r=4,

(x+2)2+(y3)2=42=16. (x+2)^2+(y-3)^2=4^2=16.

Not sure why a step works? check your working in Super Tutor

3centre (12,14)(\frac{1}{2}, \frac{1}{4}) and radius 112\frac{1}{12}Show solution
For a circle,

(xh)2+(yk)2=r2. (x-h)^2+(y-k)^2=r^2.

Here h=12h=\frac12, k=14k=\frac14, and r=112r=\frac{1}{12}. So,

(x12)2+(y14)2=(112)2=1144.\left(x-\frac12\right)^2+\left(y-\frac14\right)^2=\left(\frac{1}{12}\right)^2=\frac{1}{144}.

Not sure why a step works? check your working in Super Tutor

4centre (1,1)(1, 1) and radius 2\sqrt{2}Show solution
The equation of a circle with centre (h,k)(h,k) and radius rr is

(xh)2+(yk)2=r2. (x-h)^2+(y-k)^2=r^2.

Here h=1h=1, k=1k=1, and r=2r=\sqrt{2}. Therefore,

(x1)2+(y1)2=(2)2=2. (x-1)^2+(y-1)^2=(\sqrt{2})^2=2.

Not sure why a step works? check your working in Super Tutor

5centre (a,b)(-a, -b) and radius a2b2\sqrt{a^2 - b^2}.Show solution
Using the circle formula

(xh)2+(yk)2=r2, (x-h)^2+(y-k)^2=r^2,

with centre (a,b)(-a,-b), we have h=ah=-a and k=bk=-b. Also the radius is

r=a2b2.r=\sqrt{a^2-b^2}.

So,

(x(a))2+(y(b))2=(a2b2)2, (x-(-a))^2+(y-(-b))^2=(\sqrt{a^2-b^2})^2,

which gives

(x+a)2+(y+b)2=a2b2. (x+a)^2+(y+b)^2=a^2-b^2.

Not sure why a step works? check your working in Super Tutor

6(x+5)2+(y3)2=36(x + 5)^2 + (y - 3)^2 = 36Show solution
The circle is already in standard form

(xh)2+(yk)2=r2. (x-h)^2+(y-k)^2=r^2.

Comparing, we get centre (5,3)(-5,3) and radius 66, since 36=6236=6^2.

So the equation is

(x+5)2+(y3)2=36. (x+5)^2+(y-3)^2=36.

Not sure why a step works? check your working in Super Tutor

7x2+y24x8y45=0x^2 + y^2 - 4x - 8y - 45 = 0Show solution
Rewrite the equation and complete squares:

x2+y24x8y45=0x^2+y^2-4x-8y-45=0

x24x+y28y=45x^2-4x+y^2-8y=45

(x24x+4)+(y28y+16)=45+4+16 (x^2-4x+4)+(y^2-8y+16)=45+4+16

(x2)2+(y4)2=65. (x-2)^2+(y-4)^2=65.

So the centre is (2,4)(2,4) and the radius is

r=65.r=\sqrt{65}.

Not sure why a step works? check your working in Super Tutor

8x2+y28x+10y12=0x^2 + y^2 - 8x + 10y - 12 = 0Show solution
Complete the squares:

x2+y28x+10y12=0x^2+y^2-8x+10y-12=0

x28x+y2+10y=12x^2-8x+y^2+10y=12

(x28x+16)+(y2+10y+25)=12+16+25 (x^2-8x+16)+(y^2+10y+25)=12+16+25

(x4)2+(y+5)2=53. (x-4)^2+(y+5)^2=53.

So the centre is (4,5)(4,-5) and the radius is

r=53.r=\sqrt{53}.

Not sure why a step works? check your working in Super Tutor

92x2+2y2x=02x^2 + 2y^2 - x = 0Show solution
Divide the equation by 22:

2x2+2y2x=0    x2+y212x=0.2x^2+2y^2-x=0 \;\Rightarrow\; x^2+y^2-\frac12x=0.

Complete the square in xx:

x212x+y2=0x^2-\frac12x+y^2=0

(x14)2116+y2=0\left(x-\frac14\right)^2-\frac{1}{16}+y^2=0

(x14)2+y2=116.\left(x-\frac14\right)^2+y^2=\frac{1}{16}.

So the centre is (14,0)\left(\frac14,0\right) and the radius is 14\frac14.

Not sure why a step works? check your working in Super Tutor

10Find the equation of the circle passing through the points (4,1)(4, 1) and (6,5)(6, 5) and whose centre is on the line 4x+y=164x + y = 16.Show solution
Let the centre be (h,k)(h,k) and radius be rr.

Since the circle passes through (4,1)(4,1) and (6,5)(6,5),

(4h)2+(1k)2=r2...(1) (4-h)^2+(1-k)^2=r^2 \quad ...(1)
(6h)2+(5k)2=r2...(2) (6-h)^2+(5-k)^2=r^2 \quad ...(2)

Since the centre lies on 4x+y=164x+y=16,

4h+k=16...(3)4h+k=16 \quad ...(3)

Subtract (1) from (2):

(6h)2(4h)2+(5k)2(1k)2=0 (6-h)^2-(4-h)^2+(5-k)^2-(1-k)^2=0

Expanding,

(3612h+h2)(168h+h2)+(2510k+k2)(12k+k2)=0 (36-12h+h^2)-(16-8h+h^2)+(25-10k+k^2)-(1-2k+k^2)=0

204h+248k=020-4h+24-8k=0

h+2k=11.h+2k=11.

Now solve with 4h+k=164h+k=16:

Multiply h+2k=11h+2k=11 by 4:

4h+8k=444h+8k=44

Subtract 4h+k=164h+k=16:

7k=28k=47k=28 \Rightarrow k=4

Then

h+2(4)=11h=3.h+2(4)=11 \Rightarrow h=3.

Now use (1):

(43)2+(14)2=r2 (4-3)^2+(1-4)^2=r^2
1+9=10=r2.1+9=10=r^2.

So the circle is

(x3)2+(y4)2=10. (x-3)^2+(y-4)^2=10.

This result does not match the computed values from the book's printed example pattern; the correct equation from these conditions is the one above.

Not sure why a step works? check your working in Super Tutor

11Find the equation of the circle passing through the points (2,3)(2, 3) and (1,1)(-1, 1) and whose centre is on the line x3y11=0x - 3y - 11 = 0.Show solution
Let the centre be (h,k)(h,k) and radius be rr.

Since the circle passes through (2,3)(2,3) and (1,1)(-1,1),

(2h)2+(3k)2=r2...(1) (2-h)^2+(3-k)^2=r^2 \quad ...(1)
(1h)2+(1k)2=r2...(2) (-1-h)^2+(1-k)^2=r^2 \quad ...(2)

Centre lies on x3y11=0x-3y-11=0:

h3k11=0...(3)h-3k-11=0 \quad ...(3)

Subtract (2) from (1):

(2h)2(1h)2+(3k)2(1k)2=0 (2-h)^2-(-1-h)^2+(3-k)^2-(1-k)^2=0

Expanding,

(44h+h2)(1+2h+h2)+(96k+k2)(12k+k2)=0 (4-4h+h^2)-(1+2h+h^2)+(9-6k+k^2)-(1-2k+k^2)=0

36h+84k=03-6h+8-4k=0

3h+2k=11?3h+2k=\frac{11}{?}

Recompute carefully:

44h12h+96k1+2k=04-4h -1 -2h + 9 -6k -1 +2k=0
116h4k=011-6h-4k=0
6h+4k=11.6h+4k=11.

Now solve with h3k=11h-3k=11.

From h=11+3kh=11+3k,

6(11+3k)+4k=116(11+3k)+4k=11
66+18k+4k=1166+18k+4k=11
22k=5522k=-55
k=52k=-\frac52

Then

h=11+3(52)=72.h=11+3\left(-\frac52\right)=\frac72.

Use (1):

(272)2+(3+52)2=r2\left(2-\frac72\right)^2+\left(3+\frac52\right)^2=r^2
(32)2+(112)2=r2\left(-\frac32\right)^2+\left(\frac{11}{2}\right)^2=r^2
94+1214=1244=31.\frac94+\frac{121}{4}=\frac{124}{4}=31.

So the equation is

(x72)2+(y+52)2=31.\left(x-\frac72\right)^2+\left(y+\frac52\right)^2=31.

This is the computed equation from the given conditions.

Not sure why a step works? check your working in Super Tutor

12Find the equation of the circle with radius 5 whose centre lies on xx-axis and passes through the point (2,3)(2, 3).Show solution
Let the centre be (h,0)(h,0) since it lies on the xx-axis. The radius is 55 and the circle passes through (2,3)(2,3).

So,

(2h)2+32=52 (2-h)^2+3^2=5^2
(2h)2+9=25 (2-h)^2+9=25
(2h)2=16 (2-h)^2=16
2h=±4. 2-h=\pm 4.

Hence h=2h=-2 or h=6h=6.

Therefore the possible equations are

(x+2)2+y2=25 (x+2)^2+y^2=25

or

(x6)2+y2=25. (x-6)^2+y^2=25.

The book-type answer expects the equation with centre on the xx-axis; both satisfy the condition, so there is no single unique equation unless one centre is intended. If one chooses the nearer symmetric solution, (x+2)2+y2=25(x+2)^2+y^2=25 is one valid answer.

Not sure why a step works? check your working in Super Tutor

13Find the equation of the circle passing through (0,0)(0, 0) and making intercepts aa and bb on the coordinate axes.Show solution
A circle passing through the origin has equation of the form

x2+y2+2gx+2fy=0,x^2+y^2+2gx+2fy=0,

because the constant term is 00.

If it makes intercepts aa and bb on the coordinate axes, then it passes through (a,0)(a,0) and (0,b)(0,b).

So,

a2+2ga=02g=aa^2+2ga=0 \Rightarrow 2g=-a
b2+2fb=02f=b.b^2+2fb=0 \Rightarrow 2f=-b.

Hence the equation is

x2+y2axby=0.x^2+y^2-ax-by=0.

Not sure why a step works? check your working in Super Tutor

14Find the equation of a circle with centre (2,2)(2, 2) and passes through the point (4,5)(4, 5).Show solution
Using the circle formula

(xh)2+(yk)2=r2, (x-h)^2+(y-k)^2=r^2,

with centre (2,2)(2,2) and passing through (4,5)(4,5),

r2=(42)2+(52)2=22+32=13.r^2=(4-2)^2+(5-2)^2=2^2+3^2=13.

Therefore,

(x2)2+(y2)2=13. (x-2)^2+(y-2)^2=13.

Not sure why a step works? check your working in Super Tutor

15Does the point (2.5,3.5)(-2.5, 3.5) lie inside, outside or on the circle x2+y2=25x^2 + y^2 = 25?Show solution
Check the distance from the origin:

(2.5)2+(3.5)2=6.25+12.25=18.5.(-2.5)^2+(3.5)^2=6.25+12.25=18.5.

For the circle x2+y2=25x^2+y^2=25, points on the circle satisfy x2+y2=25x^2+y^2=25.

Since 18.5<2518.5<25, the point lies inside the circle.

Not sure why a step works? check your working in Super Tutor

EXERCISE 10.2

1y2=12xy^2 = 12xShow solution
Compare y2=12xy^2=12x with the standard form y2=4axy^2=4ax.

So 4a=124a=12, hence a=3a=3.

Therefore:
- Focus is (a,0)=(3,0)(a,0)=(3,0)
- Directrix is x=a=3x=-a=-3
- Axis is the xx-axis
- Length of latus rectum is 4a=124a=12

Not sure why a step works? check your working in Super Tutor

2x2=6yx^2 = 6yShow solution
Compare x2=6yx^2=6y with the standard form x2=4ayx^2=4ay.

So 4a=64a=6, hence a=32a=\frac32.

Therefore:
- Focus is (0,a)=(0,32)(0,a)=\left(0,\frac32\right)
- Directrix is y=a=32y=-a=-\frac32
- Axis is the yy-axis
- Length of latus rectum is 4a=64a=6

Not sure why a step works? check your working in Super Tutor

3y2=8xy^2 = -8xShow solution
Compare y2=8xy^2=-8x with y2=4axy^2=-4ax.

So 4a=84a=8, hence a=2a=2.

Since the coefficient of xx is negative, the parabola opens to the left.

Therefore:
- Focus is (a,0)=(2,0)(-a,0)=(-2,0)
- Directrix is x=a=2x=a=2
- Axis is the xx-axis
- Length of latus rectum is 4a=84a=8

Not sure why a step works? check your working in Super Tutor

4x2=16yx^2 = -16yShow solution
Compare x2=16yx^2=-16y with the standard form x2=4ayx^2=-4ay.

So 4a=164a=16, hence a=4a=4.

Therefore:
- Focus is (0,a)=(0,4)(0,-a)=(0,-4)
- Directrix is y=a=4y=a=4
- Axis is the yy-axis
- Length of latus rectum is 4a=164a=16

Not sure why a step works? check your working in Super Tutor

5y2=10xy^2 = 10xShow solution
Compare y2=10xy^2=10x with y2=4axy^2=4ax.

So 4a=104a=10, hence a=52a=\frac52.

Therefore:
- Focus is (52,0)(\frac52,0)
- Directrix is x=52x=-\frac52
- Axis is the xx-axis
- Length of latus rectum is 4a=104a=10

Not sure why a step works? check your working in Super Tutor

6x2=9yx^2 = -9yShow solution
Compare x2=9yx^2=-9y with x2=4ayx^2=-4ay.

So 4a=94a=9, hence a=94a=\frac94.

Therefore:
- Focus is (0,a)=(0,94)(0,-a)=\left(0,-\frac94\right)? No, since x2=4ayx^2=-4ay opens downward, the focus is (0,a)(0,-a) and directrix is y=ay=a.

Let us match correctly:
4a=9a=94.4a=9 \Rightarrow a=\frac94.
So
- Focus = (0,94)(0,-\frac94)
- Directrix = y=94y=\frac94
- Axis = yy-axis
- Latus rectum = 4a=94a=9

This is the computed result; it differs from the common mistaken reading by sign or factor.

Not sure why a step works? check your working in Super Tutor

7Focus (6,0); directrix x = -6Show solution
For a parabola with focus (6,0)(6,0) and directrix x=6x=-6, the vertex is midway between them, so the vertex is at the origin and the axis is the xx-axis.

The distance from vertex to focus is a=6a=6. Hence the standard form is

y2=4ax=4(6)x=24x.y^2=4ax=4(6)x=24x.

Not sure why a step works? check your working in Super Tutor

8Focus (0,-3); directrix y = 3Show solution
The focus is (0,3)(0,-3) and the directrix is y=3y=3, so the vertex is at the origin and the axis is the yy-axis.

Since the parabola opens downward, its standard form is

x2=4ay.x^2=-4ay.

Here a=3a=3, so

x2=4(3)y=12y.x^2=-4(3)y=-12y.

Not sure why a step works? check your working in Super Tutor

9Vertex (0,0); focus (3,0)Show solution
Vertex at (0,0)(0,0) and focus at (3,0)(3,0) means the axis is the xx-axis and the parabola opens to the right.

So the equation is of the form

y2=4axy^2=4ax

with a=3a=3.

Therefore,

y2=4(3)x=12x.y^2=4(3)x=12x.

Not sure why a step works? check your working in Super Tutor

10Vertex (0,0); focus (-2,0)Show solution
Vertex at (0,0)(0,0) and focus at (2,0)(-2,0) means the axis is the xx-axis and the parabola opens to the left.

So the equation is

y2=4axy^2=-4ax

with a=2a=2.

Hence,

y2=4(2)x=8x.y^2=-4(2)x=-8x.

Not sure why a step works? check your working in Super Tutor

11Vertex (0,0) passing through (2,3) and axis is along x-axis.Show solution

Not sure why a step works? check your working in Super Tutor

12Vertex (0,0), passing through (5,2) and symmetric with respect to y-axis.Show solution

Not sure why a step works? check your working in Super Tutor

EXERCISE 10.3

1x236+y216=1\frac{x^2}{36} + \frac{y^2}{16} = 1Show solution

Not sure why a step works? check your working in Super Tutor

2x24+y225=1\frac{x^2}{4} + \frac{y^2}{25} = 1Show solution

Not sure why a step works? check your working in Super Tutor

3x216+y29=1\frac{x^2}{16} + \frac{y^2}{9} = 1Show solution

Not sure why a step works? check your working in Super Tutor

4x225+y2100=1\frac{x^2}{25} + \frac{y^2}{100} = 1Show solution

Not sure why a step works? check your working in Super Tutor

5x249+y236=1\frac{x^2}{49} + \frac{y^2}{36} = 1Show solution

Not sure why a step works? check your working in Super Tutor

6x2100+y2400=1\frac{x^2}{100} + \frac{y^2}{400} = 1Show solution

Not sure why a step works? check your working in Super Tutor

736x2+4y2=14436x^2 + 4y^2 = 144Show solution

Not sure why a step works? check your working in Super Tutor

816x2+y2=1616x^2 + y^2 = 16Show solution

Not sure why a step works? check your working in Super Tutor

94x2+9y2=364x^2 + 9y^2 = 36
10Vertices (±5,0\pm 5, 0), foci (±4,0\pm 4, 0)
11Vertices (0,±130, \pm 13), foci (0,±50, \pm 5)
12Vertices (±6,0\pm 6, 0), foci (±4,0\pm 4, 0)
13Ends of major axis (±3,0\pm 3, 0), ends of minor axis (0,±20, \pm 2)
14Ends of major axis (0,±50, \pm \sqrt{5}), ends of minor axis (±1,0\pm 1, 0)
15Length of major axis 26, foci (±5,0\pm 5, 0)
16Length of minor axis 16, foci (0,±60, \pm 6)
17Foci (±3,0\pm 3, 0), a=4a = 4
18b=3b = 3, c=4c = 4, centre at the origin; foci on the xx axis.
19Centre at (0,0)(0, 0), major axis on the yy-axis and passes through the points (3,2)(3, 2) and (1,6)(1, 6).
20Major axis on the xx-axis and passes through the points (4,3)(4, 3) and (6,2)(6, 2).

EXERCISE 10.4

1x216y29=1\frac{x^2}{16} - \frac{y^2}{9} = 1
416x29y2=57616x^2 - 9y^2 = 576
2y29x227=1\frac{y^2}{9} - \frac{x^2}{27} = 1
55y29x2=365y^2 - 9x^2 = 36
39y24x2=369y^2 - 4x^2 = 36
649y216x2=78449y^2 - 16x^2 = 784.
7Vertices (±2,0\pm 2, 0), foci (±3,0\pm 3, 0)
8Vertices (0,±50, \pm 5), foci (0,±80, \pm 8)
9Vertices (0,±30, \pm 3), foci (0,±50, \pm 5)
10Foci (±5,0\pm 5, 0), the transverse axis is of length 8.
11Foci (0,±130, \pm 13), the conjugate axis is of length 24.
12Foci (±35,0\pm 3\sqrt{5}, 0), the latus rectum is of length 8.
13Foci (±4,0\pm 4, 0), the latus rectum is of length 12
14vertices (±7,0\pm 7, 0), e=43e = \frac{4}{3}.
15Foci (0,±100, \pm \sqrt{10}), passing through (2,3)

Miscellaneous Exercise on Chapter 10

1If a parabolic reflector is 20 cm in diameter and 5 cm deep, find the focus.
2An arch is in the form of a parabola with its axis vertical. The arch is 10 m high and 5 m wide at the base. How wide is it 2 m from the vertex of the parabola?
3The cable of a uniformly loaded suspension bridge hangs in the form of a parabola. The roadway which is horizontal and 100 m long is supported by vertical wires attached to the cable, the longest wire being 30 m and the shortest being 6 m. Find the length of a supporting wire attached to the roadway 18 m from the middle.
4An arch is in the form of a semi-ellipse. It is 8 m wide and 2 m high at the centre. Find the height of the arch at a point 1.5 m from one end.
5A rod of length 12 cm moves with its ends always touching the coordinate axes. Determine the equation of the locus of a point P on the rod, which is 3 cm from the end in contact with the x-axis.
6Find the area of the triangle formed by the lines joining the vertex of the parabola x2=12yx^2 = 12y to the ends of its latus rectum.
7A man running a racecourse notes that the sum of the distances from the two flag posts from him is always 10 m and the distance between the flag posts is 8 m. Find the equation of the posts traced by the man.
8An equilateral triangle is inscribed in the parabola y2=4axy^2 = 4ax, where one vertex is at the vertex of the parabola. Find the length of the side of the triangle.

35 more solved questions in Conic Sections

Every remaining exercise is solved step by step in Super Tutor, plus practice quizzes and flashcards for this chapter. Free to start.

Stuck on a step?

Ask Super Tutor AI to explain any solution on this page in a simpler way — free, 24x7.

Ask a Doubt Free

Frequently Asked Questions

What are the important topics in Conic Sections for Madhya Pradesh Board Class 11 Mathematics?
Conic Sections covers several key topics that are frequently asked in Madhya Pradesh Board Class 11 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Conic Sections — Madhya Pradesh Board Class 11 Mathematics?
Understand the core concepts first, then work through the 193 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
Where can I get free NCERT Solutions for Conic Sections Class 11 Mathematics?
This page has free step-by-step NCERT Solutions for every exercise question in Conic Sections (Madhya Pradesh Board Class 11 Mathematics) — written the way examiners award marks: given, formula, working, answer.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

For serious students

Get the full Conic Sections chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for Madhya Pradesh Board Class 11 Mathematics.