11th Grade > Mathematics
CONIC SECTIONS MCQs
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A
Radius = perpendicular distance from (1, -3) to the given line 3x - 4y - 5 = 0.
i.e. ∣∣∣3+12−5√52∣∣∣=2.
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C
Radius = √(1–4)2+(2−6)2=5
Hence the area is given by πr2=25π sq. units.
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C
Since the axis of parabola is y-axis
∴ Equation of parabola x2=4ay
Since it passes through (6 , -3)
∴ 36 = -12 a ⇒a=−3
∴ Equation of parabola is x2=−12y .
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B
y2=4.15x;a=15 . Focus is (15,0) and co-ordinates of latus rectum are y2=425⇒y=±25
or end points of latus rectum are (15,±25) .
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D
The given hyperbola is x2−y2=9
⇒x29−y29=1
a=3, b=3, c=√a2+b2=3√2
The equation of the directrices are x=±a2c
Distance between directrices,
d=2a2c=183√2=3√2
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C
The hyperbola is of the form
x2a2−y2b2=1
The transverse axis of the hyperbola is along the x-axis. Given that 2x + 3y-6=0 is a focal chord. Let (c,0) be the focus.
⇒2c+0−6=0⇒c=3Given, e=54 a=ce=125
The length of the transverse axis is 2a=245
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The eccentricity of any conic is the ratio of its distances from the focus and directrix. Let d be the distance of the point P from the directrix. Since P lies on the ellipse,
6d=35⇒d=10
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A
For the given hyperbola, Length of the transverse axis = 2a
2a= 2cos t⇒a = cos t
Consider the ellipse
9x2+16y2=144⇒x216+y29=1Focal length, c=√16−9=√7
This is the same as the focal length of the hyperbola.
Now, for the hyperbola,
b2=c2−a2b2=7−cos2t
The equation of the hyperbola is
x2cos2t−y27−cos2t=1
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Consider the following hyperbola
x2144−y225=11313 x2144−13 y225=1a2=14413; b2=2513Focal length, c=√a2+b2c=√144+2513=√16913=√13
Also, this is the focus of the ellipse
x225+y2b2=1c2=a2−b2⇒13=25−b2b2=12
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A
Let the transverse axis be along the x-axis such that the hyperbola is of the form
x2a2−y2b2=1
Latus Rectum = 2b2a=4√3
Also, 2a=2√3⇒a=√3
2b2√3=4√3⇒b2=6
The equation of the hyperbola is
x23−y26=1