Eamcet - Maths - Parabola Question And Answers

If z = log (tan x + tan y), then (sin 2x)∂z /∂x+(sin 2y) ∂z /∂y is equal to

A.  1

B.  2

C.  3

D.  4

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The line y = x√2 + λ is a normal to the parabola y2 = 4ax, then λ =

A.  4√2

B.  -4√2

C.  2√2

D.  -2√2

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The point on the parabola y = x2 + 7x + 2 closest to the line y = 3x – 3 is

A.  (2,8)

B.  (2,-8)

C.  (-2,8)

D.  (-2,-8)

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If the lines 2x + 3y + 12 = 0,x – y + 4k = 0 are conjugate with respect to the parabola y2 = 8x then k =

A.  10

B.  7/2

C.  -12

D.  -2

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I .thev locusv of the midpoints of chords of the parabola y2 = 4ax which substends a right angle at the vertex is y2 = 2a (x – 4a) II. the locus of midpoint of chords of the parabola y2 = 4ax which touch the circle X2 + y2 = a2 is (y2- 2ax)2 = a2 (y2 + 4a2)  

A.  Only I is true

B.  Only II is true

C.  Both I and II are true

D.  Neither I nor II true

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The equation of the common tangent to x2+ y2 = 8 and y2 = 16x is

A.  Y = ± (x+ 2)

B.  Y = ±(x + 4)

C.  2x + 3y + 36 = 0

D.  3x + 2y + 24 = 0

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The length of the focal chord of the parbola y2 = 4ax which makes an angle θ with its axis is

A.  4a sin2 θ

B.  4a cos2 θ

C.  4 cos2 θ

D.  4a sec2 θ

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L and L’are ends of the latus rectum of the parabola x2 = 6y. the equation of OL and OL’ where O is the origin is

A.  X2 + 4y2 = 0

B.  X2 – 4y2 = 0

C.  X2 + 2y2 = 0

D.  X2 – 2y2 = 0

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The angle subtended at the focus by the normal chord of a parabola y2= 4ax at a point whose ordinate equal to abscisa is

A.  Focus

B.  Vertex

C.  End of the latusrectum

D.  None

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If P (at21,2at1)and Q (at22,2at2),are variable points on the curve y2 = 4ax and PQ subtends a right angle at the vertex , than t1t2 =

A.  -1

B.  -2

C.  -3

D.  -4

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The equation to the normal to the parabola y2 = 4x at (1,2) is

A.  X + y -3 = 0

B.  X + y +6 = 0

C.  X – y + 5 = 0

D.  X -y + 4= 0

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Match the following Parabola Focus y2 –x – 2y + 2 = 0 (1,2) y2 – 8x – 4y – 4 = 0 (-2,5) x2 + 4x – 8y + 28 = 0 (1,-1) x2 – 2x – 8y – 23 = 0 (5/4,1)

A.  A,b,c,d

B.  B,c,a,d

C.  D,a,b,c

D.  B,d a,c

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The locus of the poles of chords of the parabola y2 = 4ax, which subtend a right angle at the vertex is

A.  X + a = 0

B.  X + 2a = 0

C.  X + 3a = 0

D.  X + 4a = 0

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If the equation of the parabola whose axis is parallel to x – axis and passing through (2,-1) (6,1) (3, -2) is ay2 + bx + cy + d = 0 then the ascending order of a,b,c,d is

A.  A,b,c,d

B.  B,c,a,d

C.  c,a,b

D.  b,a,c

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if the focus is (1,-1) and the directrix is the line x + 2y – 9 = 0, the vertex of the parabola is at

A.  (1,2)

B.  (2,1)

C.  (1,-2)

D.  (2,-1)

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I : If the points (2,-1), (5,k) are conjugate with respect to the parabola x2 = 8y then k = 7 II: If the lines 2x + 3y + 12 = 0,x – y + k = 0 are conjugate with respect to the parabola y2 = 8x then k = -12

A.  Only I is true

B.  Only II is true

C.  Both I and II are true

D.  Neither I nor II true

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If the normal at (1,2) on the parabola again at the point (l2,2t), then the value of t is

A.  1

B.  3

C.  -3

D.  1

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If P is a point on the parabola y2 = 4ax such that the subtangent and subnormal at P are equal, then the coridinate of P are

A.  (a,2a) or (a,-2a)

B.  (2a,2√2a) or (2 - ,2√2A)

C.  (4a,-4a) or (4a,4a)

D.  None

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The tangents to the parabola y2 = 4ax at p (t1) and Q (t2) intersect at R. the area of Δ PQR is

A.  1/2  a2 (t1- t2)2

B.  1/2  a1(t1-t2)

C.  1/2  a1 (t1-t2)3

D.  None

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The point on the parabola y2 = 36x whose oridinate is three times its abscissa is

A.  (4, 12)

B.  (-4, 12)

C.  (4, -12)

D.  (-4, -12)

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the equation of the parabola whose axis is parallel to x –axis and passing through (- 2,1), (1,2), (-1,3) is

A.  5y2 + 2x – 21y + 20 = 0

B.  15y2 + 12x – 11y + 10 = 0

C.  18y2 – 12x + 21y + 56 = 0

D.  25y2 – 2x -65y + 120 = 0

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The length of the latus rectum of the parabola x2 + 4x – 8y + 28 = 0 is

A.  16

B.  4

C.  2

D.  8

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The equation of the axis of the parabola 3x2 – 9x + 5y -2 = 0 is

A.  X – 2 =0

B.  X – 1 = 0

C.  X – 3 = 0

D.  2x – 3 = 0

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The sub-tangent, ordinate and sub-normal to the parabola y2 = 4ax at a point ( diffferent from the origin ) are in

A.  A.P.

B.  H.P.

C.  G.P.

D.  None

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The length of the chord intercepted bt the parabola y = x2 + 3x  on the line x + y = 5 is

A.  3 √26

B.  2√26

C.  2√2

D.  None

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The equation of the axis of the parabola (y + 3)2 = 4(x – 2) is

A.  X – 5 = 0

B.  Y  + 3 = 0

C.  2x – 1 = 0

D.  Y – 1 = 0

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Two straight lines are perpendicular to each other. One of them touches the parabola y2 = 4a (x + a) and the other touches y2 = 4b (x + b). the locus of the point of intersectionof the two lines is

A.  X + a = 0

B.  X + b = 0

C.  X  + a + b = 0

D.  X – a – b = 0

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The locus of the point of intersection of two tangents to the parabola y2 = 4ax which make the angle θ1 and θ2 with the axis so that cot θ1 + cos θ2 = k is

A.  Kx – y = 0

B.  Kx – a = 0

C.  Y – ka = 0

D.  X – ka = 0

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The equation of the axis of the parabola (y + 3)2 = 4(x – 2) is

A.  X – 5 = 0

B.  Y  + 3 = 0

C.  2x – 1 = 0

D.  Y – 1 = 0

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The equation of the tangent to the parabola y2 = 12x at (3, -6) is

A.  X + y + 3 = 0

B.  X + y + 1 = 0

C.  X – y + 2a = 0

D.  X + y + 1 = 0

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