12th Grade > Mathematics
ELLIPSE AND HYPERBOLA MCQs
Total Questions : 30
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Answer: Option D. -> None of these
:
D
Sides of the square will be perpendicular tangents to the ellipse so, vertices of the square will lie on director circle. So diameter of director circle is
2√(a2−3)+(a+4)=√2a2+2a22√a2+a+1=2a⇒a=−1Butforellipsea2>3&a>−4
So there is no value of a which satisfy both.
:
D
Sides of the square will be perpendicular tangents to the ellipse so, vertices of the square will lie on director circle. So diameter of director circle is
2√(a2−3)+(a+4)=√2a2+2a22√a2+a+1=2a⇒a=−1Butforellipsea2>3&a>−4
So there is no value of a which satisfy both.
Answer: Option D. -> π2
:
D
The given circle is the director circle of the ellipse,so the angle between the tangents is π2.
:
D
The given circle is the director circle of the ellipse,so the angle between the tangents is π2.
Answer: Option C. -> (x+2)240+y249=1
:
C
A(−2,−3),B(−2,3)
Let the third vertex be C(x,y)
AB + BC+CA=20
BC+CA=14
So locus of C is ellipse with A,B as focii.
2a=14
2ae=6
e=37
∴ we get b as √40
∴ Equation of ellipse is (x+2)240+y249=1
:
C
A(−2,−3),B(−2,3)
Let the third vertex be C(x,y)
AB + BC+CA=20
BC+CA=14
So locus of C is ellipse with A,B as focii.
2a=14
2ae=6
e=37
∴ we get b as √40
∴ Equation of ellipse is (x+2)240+y249=1
Answer: Option B. -> x2+3xy+2y2+2x+3y+2=0
:
B
We know that,
Equation of hyperbola + Equation of conjugate
hyperbola = 2(Equation of asymptotes)
∴ Equation of conjugate hyperbola
= 2 Equation of asymptotes - Equation of hyperbola
C(x, y) = 2A(x, y) – H(x, y) …… (i)
∵ H(x,y)≡x2+3xy+2y2+2x+3y=0
∴ Equation of asymptotes is
x2+3xy+2y2+2x+3y+λ=0
∴ Δ=0,abc+2fgh−af2−bg2−ch2=0,thenλ=1
∴ A(x,y)≡x2+3xy+2y2+2x+3y+1=0
∴ C(x,y)≡x2+3xy+2y2+2x+3y+2=0[from equation (i)]
:
B
We know that,
Equation of hyperbola + Equation of conjugate
hyperbola = 2(Equation of asymptotes)
∴ Equation of conjugate hyperbola
= 2 Equation of asymptotes - Equation of hyperbola
C(x, y) = 2A(x, y) – H(x, y) …… (i)
∵ H(x,y)≡x2+3xy+2y2+2x+3y=0
∴ Equation of asymptotes is
x2+3xy+2y2+2x+3y+λ=0
∴ Δ=0,abc+2fgh−af2−bg2−ch2=0,thenλ=1
∴ A(x,y)≡x2+3xy+2y2+2x+3y+1=0
∴ C(x,y)≡x2+3xy+2y2+2x+3y+2=0[from equation (i)]
Answer: Option B. -> √2
:
B
In case of rectangular hyperbola,
a=b⇒b2=a2⇒a2(e2−1)=a2⇒e=√2
:
B
In case of rectangular hyperbola,
a=b⇒b2=a2⇒a2(e2−1)=a2⇒e=√2
Answer: Option D. -> 8√3π
:
D
The path he runs is an ellipse whose major axis is 4m,e=12
Area=π ab
:
D
The path he runs is an ellipse whose major axis is 4m,e=12
Area=π ab
Answer: Option D. -> An ellipse with length of latus rectrum is 2 units
:
D
x2+y2=1; x2+2y2=4
Let R(x1,y1) is point of intersection of tangents drawn at P,Q to ellipse ⇒ PQ is chord of contact of R(x1,y1)
⇒xx1+2yy1−4=0
This touches circle ⇒r2(l2+m2)=n2⇒1(x21+4y21)=16⇒x2+4y2=16isellipsewitheccentricitye=√32andlengthoflatusrectumLL1=2
:
D
x2+y2=1; x2+2y2=4
Let R(x1,y1) is point of intersection of tangents drawn at P,Q to ellipse ⇒ PQ is chord of contact of R(x1,y1)
⇒xx1+2yy1−4=0
This touches circle ⇒r2(l2+m2)=n2⇒1(x21+4y21)=16⇒x2+4y2=16isellipsewitheccentricitye=√32andlengthoflatusrectumLL1=2
Answer: Option B. -> a2b2a2+b2
:
B
Let (asecθ,btanθ) be the any point on the hyperbola x2a2−y2b2=1
The equations of the asymptotes of the given hyperbola are xa−yb=0 and xa+yb=0
Now, p1 = length of the perpendicular from (asecθ,btanθ) on xa+yb=0
=secθ−tanθ√1a2+1b2
and p2 = length of the perpendicular from (asecθ,btanθ) xa+yb=0
=secθ−tanθ√1a2+1b2
∴ p1p2=sec2θ−tan2θ1a2+1b2=a2b2a2+b2
:
B
Let (asecθ,btanθ) be the any point on the hyperbola x2a2−y2b2=1
The equations of the asymptotes of the given hyperbola are xa−yb=0 and xa+yb=0
Now, p1 = length of the perpendicular from (asecθ,btanθ) on xa+yb=0
=secθ−tanθ√1a2+1b2
and p2 = length of the perpendicular from (asecθ,btanθ) xa+yb=0
=secθ−tanθ√1a2+1b2
∴ p1p2=sec2θ−tan2θ1a2+1b2=a2b2a2+b2
Answer: Option A. -> 3x – 4y = 4
:
A
By T = S1, the equation of chord whose mid-point is (α,β) is 3xα−2yβ+(x+α)−2(y+β)=0
⇒ x(3α+2)−y(2β+3)=2
as it is parallel to y = 2x
∴ 3α–4β=4
∴ Required locus is 3x – 4y = 4
:
A
By T = S1, the equation of chord whose mid-point is (α,β) is 3xα−2yβ+(x+α)−2(y+β)=0
⇒ x(3α+2)−y(2β+3)=2
as it is parallel to y = 2x
∴ 3α–4β=4
∴ Required locus is 3x – 4y = 4