jee-advanced

1999 jee-advanced_1999.pdf

33 maths questions

Q3 Proof by induction Prove a Binomial Identity or Inequality View
3. Let n be any positive integer. Prove that:
$$\sum _ { k = 0 } ^ { m } \frac { \binom { 2 n - k } { k } } { \binom { 2 n - k } { n } } \cdot \frac { ( 2 n - 4 k + 1 ) } { ( 2 n - 2 k + 1 ) } 2 ^ { n - 2 k } = \frac { \binom { n } { m } } { \binom { 2 n - 2 m } { n - m } } 2 ^ { n - 2 m }$$
for each nonnegative integer $\mathrm { m } \leq \mathrm { n }$. (Here $\left. \binom { p } { q } = \square ^ { p } C _ { q } \right)$
4. Let $A B C$ be a triangle having $O$ and $I$ as its circumcentre and incentre respectively. If $R$ and $r$ are the circumradius and the inradius, respectively, then prove that (IO) $2 = R 2 - 2 R r$. Further show that the triangle BIO is a right-angled triangle if and only if $b$ is the arithmetic mean of a and c.
5. Let $\mathrm { T } 1 , \mathrm {~T} 2$ be two tangents drawn from $( - 2,0 )$ onto the circle $\mathrm { C } : \mathrm { x } 2 + \mathrm { y } 2 = 1$. Determine the circles touching C and having T1, T2 as their pair of tangents. Further, find the equations of all possible common tangents to these circles, when taken two at a time.
6. Consider the family of circles $x 2 + y 2 = r 2,2 < r < 5$. If in the first quadrant, the common tangent to a circle of this family and the ellipse $4 \times 2 + 25 y 2 = 100$ meets the coordinate axes at A and B , then find the equation of the locus of the mid point of AB .
7. Integrate
(A) $\int \frac { x ^ { 3 } + 3 x + 2 } { \left( x ^ { 2 } + 1 \right) ^ { 2 } ( x + 1 ) } \mathrm { dx }$.
(B) $\quad \int _ { 0 } ^ { \pi } \frac { e ^ { \cos x } } { e ^ { \cos x } + e ^ { - \cos x } } \mathrm { dx }$. 8. Let $\mathrm { f } ( \mathrm { x } )$ be a continuous function given by
$$f ( x ) = \left\{ \begin{array} { c c } 2 x , & | x | \leq 1 \\ x ^ { 2 } + a x + b , & | x | > 1 \end{array} \right.$$
Find the area of the region in the third quadrant bounded by the curves $x = - 2 y 2$ and $y = \mathrm { f } ( \mathrm { x } )$ lying on the left on the line $8 \mathrm { x } + 1 = 0$. 9. Find the co-ordinates of all the P on the ellipse $\mathrm { x } 2 / \mathrm { a } 2 + \mathrm { y } 2 / \mathrm { b } 2 = 1$, for which the area of the triangle PON is maximum, where O denotes the origin and N , the foot of the perpendicular from O to the tangent at P . 10. A curve passing through the point $( 1,1 )$ has the property that the perpendicular distance of the origin from the normal at any point P of the curve is equal to the distance of P from the x -axis. Determine the equation of the curve. 11. Eight players $\mathrm { P } 1 , \mathrm { P } 2 , \ldots \ldots . \mathrm { P } 8$ play a knock-out tournament. It is known that whenever the players Pi and Pj play, the play Pi will win if $\mathrm { i } < \mathrm { j }$. Assuming that the players are paired at random in each round, what is the probability that the player P4 reaches the final? 12. Let $\vec { u }$ and $\vec { v }$ be unit vectors. If $\vec { w }$ is a vector such that $\vec { w } + ( \vec { w } \times \vec { u } ) = \vec { v }$, then prove that $| ( \vec { u } \times \vec { v } ) \cdot \vec { w } | \leq \frac { 1 } { 2 }$ and that the equality holds if and only if $\vec { u }$ is perpendicular to $\vec { v }$.
Q8 Indefinite & Definite Integrals Piecewise/Periodic Function Integration View
8. If for a real number $y , [ y ]$ is the greatest integer less than or equal to $y$, then the value of the integral $\int \sqcap / 23 \sqcap / 2 [ 2 \sin x . d x ]$ is:
(A) $- \pi$
(B) 0
(C) $- \pi / 2$
(D) $\pi / 2$
Q9 Arithmetic Sequences and Series Arithmetic-Geometric Hybrid Problem View
9. Let $\mathrm { a } 1 , \mathrm { a } 2 , \ldots \ldots , \mathrm { a } 10$ be in A.P. and h1, h2, ……, h10 be in H.P. If a1 $= \mathrm { h } 1 = 2$ and a10 = $\mathrm { h } 10 = 3$, then a4 h7 is :
(A) 2
(B) 3
(C) 5
(D) 6
Q10 Vectors Introduction & 2D Magnitude of Vector Expression View
10. Let $\vec { a } = 2 \hat { \imath } + \hat { \jmath } - 2 \hat { k }$ and $\hat { b } = \hat { \imath } + \hat { \jmath }$. If $\hat { c }$ is a vector such that $\vec { a } \cdot \vec { c } = | \vec { c } - \vec { a } | = 2 \sqrt { 2 }$ and the angle between $( \vec { a } \times \vec { b } )$ and $\vec { c }$ is $30 ^ { \circ }$, then $| ( \vec { a } \times \vec { b } ) \times \vec { c } | =$
(A) $\frac { 3 } { 2 }$
(B) $\frac { 3 } { 2 }$
(C) 2
(D) 3
Q11 Standard trigonometric equations Inverse trigonometric equation View
11. The number of real solutions of $\tan - 1 \sqrt { } ( x ( x + 1 ) ) + \sin - 1 \sqrt { } ( x 2 + x + 1 ) = \pi / 2$ is:
(A) zero
(B) one
(C) two
(D) infinite
Q12 Conic sections Tangent and Normal Line Problems View
12. Let $\mathrm { P } ( \mathrm { a } \sec \mathrm { q } , \mathrm { b } \tan \mathrm { q } )$ and $\mathrm { Q } ( \mathrm { a } \sec \mathrm { q } , \mathrm { b } \tan \mathrm { q } )$ where $\mathrm { q } + \mathrm { q } = \pi / 2$, be two points on the hyperbola $\times 2 / \mathrm { a } 2 - \mathrm { y } 2 / \mathrm { b } 2 =$ 1. If ( $\mathrm { h } , \mathrm { k }$ ) is the point of intersection of the normals at P and Q , then K is equal to :
(A) $( a 2 + b 2 ) / a$
(B) $- ( ( a 2 + b 2 ) / a )$
(C) $( a 2 + b 2 ) / b$
(D) $- ( ( a 2 + b 2 ) / b )$
Q13 Straight Lines & Coordinate Geometry Slope and Angle Between Lines View
13. Let $P Q R$ be a right angled isosceles triangle, right angled at $P ( 2,1 )$. If the equation of the line $Q R$ is $2 x + y = 3$, then the equation representing the pair of lines $P Q$ and $P R$ is :
(A) $3 x 2 - 3 y 2 + 8 x y + 20 x + 10 y + 25 = 0$
(B) $3 x 2 - 3 y 2 + 8 x y - 20 x - 10 y + 25 = 0$
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(C) $3 x 2 - 3 y 2 + 8 x y + 10 x + 15 y + 20 = 0$
(D) $3 x 2 - 3 y 2 - 8 x y - 10 x - 15 y - 20 = 0$
Q14 Factor & Remainder Theorem Polynomial Construction from Root/Value Conditions View
14. If $\mathrm { f } ( \mathrm { x } ) \left| \begin{array} { c c c } 1 & x & x + 1 \\ 2 x & x ( x - 1 ) & ( x + 1 ) x \\ 3 x ( x - 1 ) & x ( x - 1 ) ( x - 2 ) & ( x + 1 ) x ( x - 1 ) \end{array} \right|$ then $\mathrm { f } ( 100 )$ is equal to :
(A) 0
(B) 1
(C) 100
(D) $\quad - 100$
15. The function $f ( x ) = [ x ] 2 - [ x 2 ]$ (where [y] is the greatest integer less than or equal to $y$ ), is discontinuous at :
(A) all integers
(B) all integers except 0 and 1
(C) all integers except 0
(D) all integers except 1
16. If two distinct chords, drawn from the point ( $p , q$ ) on the circle $x 2 + y 2 = p x + q y$ (where $p q { } ^ { 1 } 0$ ) are bisected by the $x$-axis, then :
(A) $\mathrm { p } 2 = \mathrm { q } 2$
(B) $p 2 = 8 q 2$
(C) $p 2 < 8 q 2$
(D) $p 2 > 8 q 2$
17. The function $f ( x ) = ( x 2 - 1 ) | x 2 - 3 x + 2 |$ is NOT differentiable at:
(A) - 1
(B) 0
(C) 1
(D) 2
18. If the roots of the equation $x 2 - 2 a x + a 2 + a - 3 = 0$ are real and less than 3,then:
(A) $a < 2$
(B) $2 < a < 3$
(C) $3 < a < 4$
(D) a $> 4$
Q19 Differential equations Verification that a Function Satisfies a DE View
19. A solution of the differential equation $( d x / d y ) 2 - x ( d x / d y ) + y = 0$ is :
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(A) $y = 2$
(B) $y = 2 x$
(B) $y = 2 x - 4$
(D) $y = 2 \times 2 - 4$
20. $\lim x \rightarrow 0 ( x \tan 2 x - 2 x \tan x ) / ( 1 - \cos 2 x ) 2$ is:
(A) $y = 2$
(B) $y = 2 x$
(C) $y = 2 x - 4$
(D) $y = 2 \times 2 - 4$
Q21 Vectors 3D & Lines Perpendicularity or Parallel Condition View
21. Let $\vec { a } = \overrightarrow { 2 } \hat { \jmath } + \hat { k } , \vec { b } = \hat { \imath } + \overrightarrow { 2 } \hat { \jmath } - \hat { k }$ and a unit vector $\vec { c }$ be coplanar. If $\vec { c }$ is perpendicular to $\vec { a }$, then $\vec { c } =$
(A) $\frac { 1 } { \sqrt { 2 } } ( - \hat { \jmath } + \hat { k } )$
(B) $\frac { 1 } { \sqrt { 3 } } ( - \hat { \imath } - \hat { \jmath } - \hat { k } )$
(C) $\frac { 1 } { \sqrt { 5 } } ( \hat { \imath } - 2 \hat { \jmath } )$
(D) $\frac { 1 } { \sqrt { 3 } } ( \hat { \imath } - \hat { \jmath } - \hat { k } )$
Q22 Binomial Theorem (positive integer n) Determine Parameters from Conditions on Coefficients or Terms View
22. If in the expansion of $( 1 + x ) n$, the coefficients of $x$ and $x 2$ are 3 and - 6 respectively, then m is :
(A) 6
(B) 9
(C) 12
(D) 24
Q23 Standard Integrals and Reverse Chain Rule Definite Integral Evaluation (Computational) View
23. $\int \sqcap / 33 \pi / 4 \mathrm { dx } / ( 1 + \cos \mathrm { x } )$ is equal to :
(A) 2
(B) - 2
(C) $1 / 2$
(D) $- 1 / 2$
Q24 Conic sections Tangent and Normal Line Problems View
24. If $x = 9$ is the chord of contact of the hyperbola $x 2 - y 2 = 0$, then the equation of the corresponding pair of tangents is :
(A) $9 x 2 - 8 y 2 + 18 x - 9 = 0$
(B) $9 x 2 - 8 y 2 - 18 x + 9 = 0$
(C) $9 x 2 - 8 y 2 - 18 x - 9 = 0$
(D) $9 x 2 - 8 y 2 + 18 x + 9 = 0$
25. If the integers $m$ and $n$ are chosen at random between 1 and 100 , then the probability that a number of the form $7 m + 7 n$ is divisible by 5 equals :
(A) $1 / 4$
(B) $1 / 7$
(C) $1 / 8$
(D) $1 / 49$
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DIRECTIONS : Question numbers $26 - 35$ carry 3 marks each and may have more than one correct answers. All correct answers must be marked to get any credit in these questions.
26. Let L1 be a straight line passing through the origin and L2 be the straight line $x + y =$ 1. If the intercepts made by the circle $x 2 + y 2 - x + 3 y = 0$ on L1 and L2 are equal, then which of the following equations can represent L1?
(A) $x + y = 0$
(B) $x - y = 0$
(B) $x + 7 y = 0$
(D) $x - 7 y = 0$
Q27 Vectors Introduction & 2D Magnitude of Vector Expression View
27. Let $\vec { a }$ and $\vec { b }$ be two non-collinear unit vectors. If $\vec { u } = \vec { a } - ( \vec { a } , \vec { b } ) \vec { b }$ and $\vec { v } = \vec { a } \times \vec { b }$, then $| \vec { v } |$ is:
(A) $| \vec { u } |$
(B) $\quad | \vec { u } | + | \vec { u } \cdot \vec { a } |$
(C) $| \vec { u } | + | \vec { u } , \vec { b } |$
(D) $| \vec { u } | + \vec { u } \cdot ( \vec { a } + \vec { b } )$
Q28 Sequences and series, recurrence and convergence Compute Partial Sum of an Arithmetic Sequence View
28. For a positive integer n , let $\mathrm { a } ( \mathrm { n } ) = 1 + 1 / 2 + 1 / 3 + 1 / 4 + \ldots \ldots + 1 / ( ( 2 \mathrm { n } ) - 1 )$. Then :
(A) a (100) £ 100
(B) a $( 100 ) > ( 100 )$
(C) a (200) $\pounds 100$
(D) a $( 200 ) > 100$
Q29 Stationary points and optimisation Composite or piecewise function extremum analysis View
29. The function $f ( x ) = \int - 1 x t$ (et-1)(t-1)(t-2)3(t-3)5dt has a local minimum at $x =$
(A) 0
(B) 1
(C) 2
(D) 3
30. On the ellipse $4 x 2 + 9 y 2 = 1$, the points at which the tangents are parallel to the line $8 \mathrm { x } = 9 \mathrm { y }$ are :
(A) $( 2 / 5,1 / 5 )$
B) $( - 2 / 5,1 / 5 )$
(C) $( - 2 / 5 , - 1 / 5 )$
(D) $( 2 / 5 , - 1 / 5 )$
Q31 Modelling and Hypothesis Testing Probability Using Set/Event Algebra View
31. The probabilities that a student passes in Mathematics, Physics and Chemistry are $\mathrm { m } , \mathrm { p }$ and c , respectively. Of these subjects, the student has a $75 \%$ chance of passing in atleast one, a $50 \%$ chance of passing in atleast two, and a $40 \%$ chance of passing in exactly two. Which of the following relations are true?
(A) $\mathrm { p } + \mathrm { m } + \mathrm { c } = 19 / 20$
(B) $p + m + c = 27 / 20$
(C) $\mathrm { pmc } = 1 / 10$
(D) $\mathrm { pmc } = 1 / 4$
Q32 Differential equations Higher-Order and Special DEs (Proof/Theory) View
32. The differential equation representing the family of curves $y 2 = 2 c ( x + \sqrt { } c )$, where $c$ is a positive parameter, is of :
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(A) order 1
(B) order 2
(C) degree 3
(D) 10
33. Let $S 1 , S 2 \ldots$ be squares such that for each $n ^ { 3 } 1$, the length of a side of Snequals the length of a diagonal of $\mathrm { Sn } + 1$. If the length of a side of S 1 is 10 cm , then for which of the following values of $n$ is the area of $S n$ less than $1 \mathrm { sq } . \mathrm { cm }$ ?
(A) 7
(B) 8
(C) 9
(D) 10
Q34 Areas by integration View
34. For which of the following values of $m$ is the area of the region bounded by the curve $y = x - x 2$ and he line $y = m x$ equals 9/2?
(A) - 4
(B) - 2
(C) 2
(D) 4
35. For a positive integer n ., let $\mathrm { f } \_ \mathrm { n } ( \theta ) = ( \tan \theta / 2 ) ( 1 + \sec \theta ) ( 1 + \sec 2 \theta ) ( 1 + \sec 4 \theta )$... $( 1 + \sec 2 \mathrm { n } \theta )$. Then
(A) $\mathrm { f } 2 ( \Pi / 16 ) = 1$;
(B) $f 3 ( \pi / 32 ) = 1$
(C) $\mathrm { f } 4 ( \pi / 16 ) = 1$
(D) f5 $( \sqcap / 128 ) = 1$
SECTION II
Instructions
There 12 questions in the section. Attempt ALL questions. At the end of the anwers to a question, draw a horizontal line and start answer to the next question. The corresponding question number must be written in the left margin. Answer all parts of a question at one place only. The use of Arabic numerals ( $0,1,2 , \ldots \ldots . .9$ ) only is allowed in answering the questions irrespective of the language in which you answer.
  1. For complex numbers z and q , prove that $| \mathrm { z } | 2 \mathrm { w } - | \mathrm { w } | 2 \mathrm { z } = \mathrm { z } - \mathrm { w }$ if and only if $\mathrm { z } = \mathrm { w }$ or z $\mathrm { w } - = 1$.
  2. Let $a , b , c d$ be real numbers in G.P. If $u , v , w$ satisfy the system of equations

$$\begin{aligned} & u + 2 v + 3 w = 6 \\ & 4 u + 5 v + 6 w = 12 \\ & 6 u + 9 v = 4 \end{aligned}$$
Then slow that the roots of the equation :
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... Powered By IITians $( 1 / u + 1 / v + 1 / w ) \times 2 + [ ( b - c ) 2 + ( c - a ) 2 + ( d - b ) 2 ] x + u + v + w = 0$ and $20 \times 2 + 10 ( a - d ) 2 x - 9 = 0$ are reciprocals of each other.