JEE Advanced Maths Assignment - NARAYANA IIT ...// JEE–Advanced Maths – Assignment Only One...
Transcript of JEE Advanced Maths Assignment - NARAYANA IIT ...// JEE–Advanced Maths – Assignment Only One...
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JEE–Advanced
Maths – Assignment Only One Correct Answer Type
1. The locus of the orthocenter of the triangle formed by the lines (1+P)x–Py + P(1+P) = 0,
(1+q)x – qy+q(1+q) = 0 and y = 0, where p ≠q, is
(a) a hyperbola (b) a parabola
(c) an ellipse (d) a straight line
2. If two different tangents of y2 = 4x are the normals to x
2 = 4by, then
(a) 1
b2 2
(b) 1
b2 2
(c) 1
b2
(d) 1
b2
3. Minimum distance between the curves 2y x 1 and
2x y 1 is equal to
(a) 3 2
4 (b)
5 2
4
(c) 7
24
(d) 1
24
4. Minimum distance between the curves 2y 4x and
2 2x y 12x 31 0 is equal to
(a) 21 (b) 26
(c) 5 (d) 28
5. Sides of a equilateral ABC touch the parabola 2y 4ax, then point A, B and C lie on
(a) 22y x a 4ax (b)
22y 3 x a ax
(c) 22y 3 x a 4ax (d)
22y x a ax
6. Length of the focal chord of the ellipse 2
2 2
x y1,
a b
that is inclined at an angle with
the x–axis, is equal to
(a) 2
2 2 2 2
2b a
a sin b cos (b)
2
2 2 2 2
2b a
a cos b sin
(c) 2
2 2 2 2
2a b
a sin b cos (d)
2
2 2 2 2
2a b
a cos b sin
7. Eccentricity of the ellipse 2 25x 6xy 5y 8
(a) 1
2 (b)
3
2
(c) 2
3 (d)
1
3
8. PQ is a chord of the ellipse 2 2
2 2
x y1.
a b If O is the centre of the ellipse and eccentric
angle of the points P and Q differ by ,2
then area of triangle OPQ is
(a) ab (b) 2ab
(c) ab / 2 (d) ab / 4
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9. An ellipse with major and minor axes of length 10 3 and 10 respectively, slides along
the co-ordinate axes and always remains confined in the first quadrant. The locus of the
centre of the ellipse will be the arc of a circle. The length of this arc will be equal to
(a) 10 units (b) 5 units
(c) 5
4 units (d)
5
3 units
10. Consider a circle 2 2 2x y d and an ellipse
2 2
2 2
x y1,
a b d > maxi. {a,b} from a
variable point P on the circle, tangents PA and PB are drawn to the ellipse. Locus of the
mid–point of chord AB is
(a) 2 2
2 2 4
2 2
x yx y d
a b
(b)
22 2
2 2 2
2 2
x yx y d
a b
(c) 2 2 2 2 4b x a y d (d)
2 2 2 2 4a x b y d
11. PQ is variable chord of the ellipse 2 2
2 2
x y1.
a b if PQ subtend a right angle at the centre
of the ellipse then 2 2
1 1,
OP OQ (O being the origin) is equal to
(a) 2 2
1 1
a b (b)
2 2
2 1
a b
(c) 2 2
1 2
a b (d)
2 2
1 12
a b
12. Consider any chord of the hyperbola xy=c2 that is parallel to the line y = x. Circles are
drawn having this chord as diameter. All these circles will pass through two fixed points
whose co–ordinates are
(a) c 2,c 2 , c 2, c 2 (b) c 2,c 2 , c 2, c 2
(c) c,c , c, c (d) c,c , c,c
13. The tangent at a point ‘P’ on the hyperbola 2 2
2 2
x y1,
a b meets one of its directix at the
point Q. If the line segment PQ subtends an angle at the corresponding focus, than is
always equal to
(a) 4
(b)
2
(c) 3
(d)
6
14. If tangent and normal to the hyperbola xy = c2, at any point ‘P’ cuts off intercept a1 and
a2 on the x–axis respectively and b1 and b2 on the y–axis, then 1 2 1 2a a b b is always
equal to
(a) –1 (b) 1
(c) 0 (d) none of these
15. Locus of the mid–point of the chord of the hyperbola 2 2 2x y a , that touch the
parabola 2y 4ax is
(a) 2x x a y (b) 2y x a y
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(c) 3 2x x a y (d) 3 2y x a x
16. Locus of the point of intersection of tangent drawn to the hyperbola 2xy c at the
extremities of any normal chord is
(a) 2
2 2 2x y c xy 0 (b) 2
2 2 2x y c xy 0
(c) 2
2 2 2x y 4c xy 0 (d) 2
2 2 2x y 4c xy 0
17. A water jet from a fountain reaches its maximum height of 4 m at a distance 0.5 m from
the vertical passing through the point O of water outlet. The height of the jet above the
horizontal OX at a distance of 0.75m from the point O is
(a) 5m (b) 6m
(c) 3m (d) 7m
18. Equation of a normal to the curve y = x2–6x + 6 which is perpendicular o the straight line
joining the origin to the vertex of the parabola is
(a) 4x – 4y – 11 = 0 (b) 4x – 4y + 1 = 0
(c) 4x – 4y – 21 = 0 (d) 4x – 4y + 21 = 0
19. A circle drawn on any focal chord of the parabola y2=4ax as diameter cuts parabola at
two points ‘t’ and ‘t’ (other than the extrimity of focal chord) the
(a) tt = –1 (b) tt = 2
(c) tt = 3 (d) none of these
20. Two parabolas with the same axis, focus of each being exterior to the other and the latus
rectum being 4a and 4b. The locus of the middle points of the intercepts between the
parabolas made on the lines parallel to the common axis is a
(a) straight line if a = b (b) parallel line if a ≠ b
(c) parabola for all a, b (d) ellipse if b > a
21. If three distinct normal can be drawn to the parabola y2 – 2y = 4x – 9 from the point
(2a, 0) then range of values of a is
(a) No real values possible (b) (2, )
(c) (– , 2) (d) none of these
22. If the curves 2
2xy 1
4 and
22
2
xy 1
a for suitable value of a cut on four concylic
points, the equation
(a) 2 2x y 2 (b)
2 2x y 1
(c) 2 2x y 4 (d) none of these
23. Angle subtended by common tangents of two ellipse 2
4 x 4 +25y2
= 100 and
2 24 x 1 y 4 at origin is
(a) 3
(b)
4
(c) 2
(d) none of these
24. If PQR be an equilateral triangle inscribed in the auxillary circle of the ellipse 2 2
2 2
x y1
a b (a>b) and PQR be corresponding triangle inscribed within the ellipse then
centriod of the triangle PQR lies at
(a) centre of ellipse (b) focus of ellipse
(c) between focus and centre of major axis (d) none of these
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25. The normal at a variable point P on the ellipse 2 2
2 2
x y1
a b , a>b of eccentricity ‘e’ meets
the axes of the ellipse Q and R then the locus of the mid point QR is coinc with a
eccentricity e such that
(a) e is independent of e (b) e = 1
(c) e = e (d) e = 1
e
26. If a variable line x cos ysin P, which is a chord of the hyperbola
2 2
2 2
x y1 b a
a b , subtends a right angle at the centre of the hyperbola then it always
touches a fixed circle whose radius is
(a) ab
b 2a (b)
a
a b
(c) 2 2
ab
b a (d)
ab
b a b
27. Let any double ordinate PNP of the hyperbola 2 2x y
125 16
be produced both sides to
meet the asymptotes in Q and Q, then PQ. PQ is equal to
(a) 25 (b) 16
(c) 41 (d) none of these
28. The equation of the line of latus rectum of the rectangular hyperbola xy = c2 is
(a) x y 2c (b) x y 2 2c
(c) x y 2c (d) x y 0
29. The line parallel to the normal to the curve xy = 1 is/are
(a) 3x 4y 5 0 (b) 3x 4y 5 0
(c) 4y 3x 5 0 (d) 3y 4x 5 0
30. The line 22px y 1 p 1 p 1 for different values of p touches
(a) An ellipse of eccentricity 2
3 (b) An ellipse of eccentricity
3
2
(c) Hyperbola of eccentricity 2 (d) none of these
31. If , are the eccentric angels of the ends of a focal chord of the ellipse 2 2
2 2
x y1,
a b
then the eccentricity of the ellipse is
(a)
sin sin
sin
(b)
sin sin
sin
(c)
cos cos
cos
(d)
cos cos
cos
32. If chords of contact of tangents from two points 1 1x , y and 2 2x , y to the ellipse
2 2
2 2
x y1
a b are at right–angle, then 1 2
1 2
x x
y y
(a) 2
2
a
b (b)
2
2
b
a
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(c) 4
4
a
b (d)
4
4
b
a
33. PM and PN are the perpendiculars from any point P on the rectangular hyperbola xy = c2
to the asymptotes. The locus of the mid–point of MN is a hyperbola with eccentricity
(a) 2 (b) 2
(c) 1
2 (d) 2 2
34. An ellipse has eccentricity 1
2 and one focus at
1s ,1
2
. Its one directix is the common
tangent, (nearer to S) to the circle 2 2x y 1 and
2 2x y 1. The equation of the
ellipse in standard form is
(a) 2
219 x 12 y 1 1
3
(b)
221
12 x 9 y 1 13
(c)
2
2
1x
y 121
12 9
(d) 2
213 x 4 y 1 1
2
35. If 1p and 2p are the perpendiculars from the origin on the straight lines
x sec ycosec 2a and x cos ysin a cos 2 , then
(a) 2 2 2
1 24p p a (b) 2 2 2
1 2p 4p a
(c) 2 2 2
1 2p p 4a (d) 2 2 2
1 2p p a
36. If c is the centre and A, B are two points on the conic 2 24x 9y 8x 36y 4 0 such
that ACB ,2
then
2 2CA CB is equal to
(a) 13
36 (b)
36
13
(c) 16
33 (d)
33
16
37. A point moves such that the sum of the squares of its distances from the two sides of
length a of a rectangle is twice the sum of the squares of its distances from the other two
sides of length b. the locus of the point can be
(a) a circle (b) an ellipse
(c) a hyperbola (d) a pair of lines
38. If the tangent at the point 1 1P x , y to the parabola 2y 4ax meets the parabola
2y 4a x b at Q and R, then the mid–point of QR is
(a) 1 1x b, y b (b) 1 1x b, y b
(c) 1 1x , y (d) 1 1x b, y
39. If , are the eccentric angels of the extremities of a focal chord of an ellipse, then the
eccentricity of the ellipse is
(a)
cos cos
cos
(b)
sin sin
sin
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(c)
cos cos
cos
(d)
sin sin
sin
40. PQ and RS are two perpendicular chords of t rectangular hyperbola xy = c2. If O is the
centre of the hyperbola, then the product of the slopes of OP, OQ, OR and OS is equal to
(a) –1 (b) 1
(c) 2 (d) 4
41. Let f be the focus of the parabola. From the end point (P) of focal chord PF
perpendicular PM is drawn to directix. From P a line is drawn through the mid–point (R)
of FM, then the angle between PR and FM is
(a) 45 (b) 60
(c) 90 (d) none of these
42. A normal drawn to parabola 2y 4ax meet the curve again at Q such that angle subtend
by PQ at vertex is 90 then coordinate of P can be
(a) 8a, 4 2a (b) 8a,4a
(c) 2a, 2 2a (d) none of these
43. If the focus of parabola (y–k)2=4(x–h) always lies between the line x + y = 1 and
x + y = 3 then
(a) 0 h k 2 (b) 0 h k 1
(c) 1 h k 2 (d) 1 h k 3
44. If xy = m2–4 be a rectangular hyperbola whose branches lies only in the 2
nd and 4
th
quadrant then
(a) m 2 (b) m 2
(c) m 2 (d) not possible
45. A tangent to the ellipse 2 2x y
125 16
at any point P meet the line x = 0 at a point Q. Let
R b the image of Q in the line y =x, then circle whose extremities of a diameter are Q
and R passes through a fixed point. The fixed point is
(A) (3,0) (B) (5,0)
(C) (0,0) (D) (4,0)
46. Number of points on the ellipse 2 2x y
150 20
from which pair of perpendicular tangents
are drawn to the ellipse 2 2x y
116 9
is
(A) 0 (B) 2
(C) 1 (D) 4
47. An ellipse is drawn with major and minor axes of lengths 10 and 8 respectively. Using
one focus and centre, a circle is drawn that is tangent to the ellipse, with no part of the
circle being outside the ellipse. The radius of the circle is :
(A) 2 (B) 3
(C) 3 (D) 4
48. A circle has the same centre as an ellipse and passes through the foci F1 and F2 of the
ellipse, such that the two curves intersect in 4 points. Let P be any one of their point
of intersection. If the major axis of the ellipse is 17 and the area of the triangle PF1F2
is 30, then the distance between the foci is
(A) 11 (B) 12
(C) 13 (D) 15
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49. Any ordinate MP of an ellipse 2 2x y
125 9
meets the auxiliary circle in Q, then locus
of point of intersection of normals at P and Q to the respective curves, is
(A) 11 (B) 12
(C) 13 (D) 15
50. Number of distinct normal lines that can be drawn to ellipse 2 2x y
1169 25
from the
point P(0,6) is
(A) one (B) two
(C) three (D) four
51. If PQ is focal chord of ellipse 2 2x y
125 16
which passes through S (3,0) and PS = 2
then length of chord PQ is
(A) 8 (B) 6
(C) 10 (D) 4
52. If P is a moving point in the xy-plane is such a way that perimeter of triangle PQR is
16 {where Q (3, 5) , R (7,3 5 )} then maximum area of triangle PQR is
(A) 6 sq. unit (B) 12 sq. unit
(C) 18 sq. unit (D) 9 sq. unit
53. If f(x) is a decreasing function then the set of values of ‘k’, for which the major axis
of the ellipse
2 2
2
x y1
f k 11f k 2k 5
is the x-axis, is
(A) k 2,3 (B) k 3,2
(C) k , 3 2, (D) k , 2 3,
54. The equation to the locus of the middle point of the portion of the tangent to the
ellipse 2 2x y
116 9
included between the co-ordinate axes is the curve
(A) 9x2
+ 16y2 = 4 x
2y
2 (B) 16x
2 + 9y
2 = 4 x
2y
2
(C) 3x2
+ 4y2 = 4 x
2y
2 (D) 9x
2 + 16y
2 = x
2y
2
55. From a point P(1,2) pair of tangent’s are drawn to a hyperbola ‘H’ in which one
tangent to each are of hyperbola. H are 3x y 5 0 and 3x y 1 0 3x y 0
then eccentricity of H is
(A) 2 (B) 2
3
(C) 2 (D) 3
56. If a variable lines has its intercepts on the coordinates axes e, e where e e
,2 2
are the
eccentricities of a hyperbola and its conjugate hyperbola, then the line always touches
the circle 2 2 2x y r , where r =
(A) 1 (B) 2
(C) 3 (D) can not be decided
57. If angle between asymptote’s of hyperbola 2 2
2 2
x y1
a b is 120 and product of
perpendiculars drawn from foci upon its any tangent is 9, then locus of point of
intersection of perpendicular tangent of the hyperbola can be
(A) 2 2x y 6 (B) 2 2x y 9
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(C) 2 2x y 3 (D) 2 2x y 18
58. C be a curve which is locus of point of intersection of lines x = 2 + m and my=4–m.
A circle 2 2
s x 2 y 1 25 intersects the curve C at four points, P, Q, R and S.
If O is centre of the curve C, then OP2 + OQ
2 + OS
2 is
(A) 50 (B) 100
(C) 25 (D) 25/2
59. The combined equation of the asymptotes of the hyperbola 2 22x 5xy 2y 4x 5y 0 is
(A) 2 22x 5xy 2y 4x 5y 2 0 (B) 2 22x 5xy 2y 4x 5y 2 0
(C) 2 22x 5xy 2y 0 (D) none of these
60. If 3 then the chord joining the points and for the hyperbola 2 2
2 2
x y1
a b
passes through
(A) focus (B) centre
(C) one of the end points of the transverse axis
(D) one of the end points of the conjugates axis
61. For a given non-zero value of m each of the lines x y
ma b and
x ym
a b meets the
hyperbola 2 2
2 2
x y
a b = 1 at a point. Sum of the ordinates of these points, is
(A) 2a 1 m
m
(B)
2b 1 m
m
(C) 0 (D) a b
2m
62. The equation of the transverse axis of the hyperbola (x-3)2 + (y+1)
2 = (4x + 3y)
2 is
(A) x + 3y = 0 (B) 4x + 3y = 9
(C) 3x – 4y = 13 (D) 4x + 3y = 0
63. For which of the hyperbola, we can have more than one pair of perpendicular
tangents ?
(A) 2 2x y
14 9 (B)
2 2x y1
4 9
(C) 2 2x y 4 (D) xy 4
64. From point (2,2) tangents are drawn to the hyperbola 2 2x y
116 9
then point of contact
lie in
(A) I and II quadrants (B) I and IV quadrants
(C) I and III quadrants (D) III and IV quadrants
65. A circle is described whose centre is the vertex and whose diameter is three-quarters
of the latus rectum of the parabola 2y 4ax. If PQ is the common chord of the circle
and the parabola and L1L2 is the latus rectum, then the area of the trapezium PL1L2Q
is
(A) 23 2a (B) 22 2a
(C) 24a (D) 22 2a
2
66. From the point (15,12) three normals are drawn to the parabola 2y 4x, then centroid
of triangle formed by three-co-normal points is
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(A) 16
,03
(B) 4,0
(C) 26
,03
(D) 6,0
67. Through the vertex O of the parabola y2 =4ax two chords OP and OQ are drawn and
the circles on OP and OQ as diameter intersect in R. If 1 2, & are the angle made
with the axis by the tangents at P and Q on the parabola and by OR then
cot 1 2cot is equal to
(A) 2tan (B) 2tan
(C) 0 (D) 2cot
68. A ray of light travels along a line y = 4 and strikes the surface of a curve 2y 4 x y
then equation of the line along reflected ray travel is
(A) x = 0 (B) x = 2
(C) x + y = 4 (D) 2x+y = 4
69. If P be a point on the parabola 2y 3 2x 3 and M is the foot of perpendicular drawn
from P on the directix of the parabola, then length of the each side of an equilateral
triangle SMP, where S is focus of the parabola, is
(A) 2 (B) 4
(C) 6 (D) 8
70. If the locus of middle point of contact of tangent drawn to the parabola 2y 8x and
foot of perpendicular drawn from its focus to the tangent is a conic then length of
latusrecturm of this conic is
(A) 9/4 (B) 9
(C) 18 (D) 9/2
71. Normals at three points P, Q, R at the parabola 2y 4ax meet in a point A and S be its
focus, if 2
SP . SQ . SR SA , then is equal to
(A) a3 (B) a
2
(C) a (D) 1
72. If the chord of contact of tangents from a point P to the parabola 2y 4ax touches the
parabola 2x 4by , the locus of P is
(A) circle (B) parabola
(C) ellipse (D) hyperbola
73. Minimum area of circle which touches the parabola’s 2y x 1 and 2y x 1 is
(A) 9
sq.unit16
(B)
9sq.unit
32
(C) 9
sq.unit8
(D)
9sq.unit
4
74. Let P and Q be points (4,-4) and (9,6) of the parabola 2y 4a x b . Let R be a point
on the arc of the parabola between P and Q. Then the area of PRQ is largest when
(A) PRQ 90 (B) then point R is (4,4)
(C) the point R is 1
,14
(D) none of these
ONE OR MORE THAN ONE CORRECT
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75. If P is a point of the ellipse 2 2
2 2
x y1
a b , whose foci are S and S. Let PSS and
PS S , then
(A) PS PS 2a, if a > b
(B) PS PS 2b, if a < b
(C) 1 e
tan tan2 2 1 e
(D) 2 2
2 2
2
a btan tan a a b
2 2 b
when a > b
76. If the chord through the points whose eccentric angles are and on the ellipse, 2 2
2 2
x x1
a b passes through a focus, then the value of tan / 2 tan / 2 is :
(A) e 1
e 1
(B)
e 1
e 1
(C) 1 e
1 e
(D)
1 e
1 e
77. The equation 2 23x 4y 18x 16y 43 c
(A) cannot represent a real pair of straight lines for any value of c
(B) represents an ellipse , if c > 0
(C) represents empty set, if c < 0
(D) a point, if c = 0
78. If foci of 2 2
2 2
x y1
a b concide with the foci of
2 2x y1
25 9 and eccentricity of the
hyperbola is 2, then
(A) 2 2a b 16
(B) there is no director circle to the hyperbola
(C) centre of the director circle is (0,0)
(D) length of latus rectum of the hyperbola = 12
79. If (5,12) and (24,7) are the foci of a conic passing through the origin then the
eccentricity of conic is
(A) 386
12 (B)
386
13
(C) 386
25 (D)
386
38
80. For the hyperbola 2 29x 16y 18x 32y 151 0
(A) One of the directrix is 21
x5
(B) length of latus rectum = 9
2
(C) Focii are (6,1) and (-4,1) (D) eccentricity is 5
4
Subjective Type 81. Two parabolas have a common axis and concavities in opposite directions; if any line
parallel to the common axis meet the parabolas in P and P, prove that the locus of the
middle point of PP is another parabola, provided that the latus recta of the given
parabolas are unequal.
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82. The normal at any point P meets the axis in G and the tangent at the vertex in G, if A be
the vertex and the rectangle AGQG be completed, prove that the equation to the locus of
Q is x3 = 2ax
2 + ay
2
83. If a normal to a parabola make an angle of with the axis, show that it will cut the curve
again at angle 1 1tan tan
2
84. If PQ be a normal chord of the parabola and if S be the focus, prove that the locus of the
centroid of the triangle SPQ is the curve
2 4 436ay 3x 5a 81y 128a
85. If from the vertex of a parabola a pair of chord be drawn at right angles to one another
and with these chords as adjacent sides a rectangle be made, prove that the locus of the
further angle of the rectangle is the parabola y2=4a(x–8a)
86. Prove that the orthocentres of the triangles formed by three tangents and the
corresponding three normals to a parabola are equidistant from the axis.
87. Circles are drawn through the vertex of the parabola to cut the parabola at the other point
of intersection.
Prove that the locus of the centres of the circles is the curve
22 2 22y 2y x 12ax ax 3x 4a
88. Through the vertex A of the parabola y2-=4ax two chords AP and AQ are drawn, and the
circles on AP and AQ as diameters intersect in R. Prove that, if 1 2, and be the
angles made with the axis by the tangents at P and Q and by AR, then
1 2cot cot 2 tan 0
89. If the normals at the three points P,Q and R meet in a point and if PP, QQ and RR be
chords parallel to QR, RP and PQ respectively, prove that the nromals at P, Q and R
and also meet in a point
90. The sides of a triangle touch a parabola and two of its angular point lie on another
parabola with its axis in the same direction; prove that the locus of the third angular
points in another parabola.
91. The tangent at any point P of a circle meets the tangent at a fixed point a in T, and T is
joined to B, the other end of the diameters through A; prove that the locus of the
intersection of AP and BT is an ellipse whose eccentricity is 1
2
92. Find the locus of intersection of the two straight lines tx y
t 0a b and
x ty1 0
a b .
Prove also that they meet at the point whose eccentric angle is 2 tan–1
t.
93. If the straight line y=mx+c meet the ellipse, prove that the equation to the circle,
described on the line joining the points of intersection as diameter, is
2 2 2 2 2 2 2 2 2 2 2 2 2a m b x y 2ma cx 2b cy c a b a b 1 m 0 .
94. Prove that the sum of the eccentric angles of the extremities of a chord, which is drawn
in a given direction, is constant and equal to twice the eccentric angle of the point at
which the tangent is parallel to the given direction.
95. The eccentric angles of two point P and Q on the ellipse are 1 and 2 ; prove that the
area of the parallelogram formed by the tangents at the ends of the diameters. Through P
and q is 4abcosec 1 2 and hence that it is least when P and q are at the end of
conjugate diameters.
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96. In both an ellipse and a hyperbola, prove that the focal distance of any point and the
perpendicular from the centre upon the tangent as it meet on a circle whose centre is the
focus and whose radius is the semi–transverse axis.
97. Given the base of a triangle and the ratio of the tangent of half the base angles, prove that
the vertex moves on a hyperbola whose foci are extremities of the base.
98. A straight line is drawn parallel to the conjugate axis of a hyperbola to meet it and the
conjugate hyperbola in the point s P and q; show that the tangents at P and Q meet on the
curve 4 2 2 2
2 2 2
y y x 4x
b b a a
99. Find the equation to the hyperbola, whose asymptotes are straight lines x+2y+3=0 and
3x+4y+5=0, and whish passes through the point (1,–1).
Write down also the equation to the conjugate hyperbola.
100. C is the centre of the hyperbola 2 2
2 2
x y1
a b and the tangent at any point P meets the
asymptote in the point q and r. Prove that the equation to the locus of the centre of the
circle circumscribing the triangle CQR is 2
2 2 2 2 2 24 a x b y a b
101. Let V be the vertex and L be the latusrectum of the parabola 2x 2y 4x 4. then the
equation of the parabola whose vertex is at V, latusrectum is L/2 and axis is
perpendicular to the axis of the given parabola.
(A) 2y x 2 (B) 2y x 4
(C) 2y 2 x (D) 2y 4 x
102. If equation of tangent at P, Q and vertex A of a parabola are 3x 4y 7 0 ,
2x + 3y-10=0 and x – y = 0 respectively, then
(A) focus is (4,5) (B) length of latus rectum is 2 2
(C) axis is x y 9 0 (D) vertex is 9 9
,2 2
103. If A and B are points on the parabola 2y 4ax with vertex O such that OA
perpendicular to OB and having length, r1 and r2 respectively, then the value of 4/3 4/3
1 2
2/3 2/3
1 2
r r
r r is
(A) 216a (B) 2a
(C) 4a (D) none of these
104. Let P, Q and R are three co-normal points on the parabola 2y 4ax. then the correct
statement(s) is / are
(A) algebraic sum of the slopes of the normals at P, Q and R vanishes
(B) algebraic sum of the ordinates of the points P, Q and R vanishes
(C) centroid of the triangle PQR lies on the axis of the parabola
(D) circle circumscribing the triangle PQR passes through the vertex of the
parabola.
105. The locus of the mid point of the focal radii of a variable point moving on the
parabola , 2y 4ax is a parabola whose
(A) latus rectum is half the latus rectum of the original parabola
(B) vertex is (a/2.0)
(C) directix is y-axis
(D) Focus has the co-ordinates (a,0)