Page 1
SECTION-A
1. Consider the system of linear equations
x + y + z = 5, x + 2y + ?
2
z = 9,
x + 3y + ?z = ?, where ?, ? ? R. Then, which of
the following statement is NOT correct?
(1) System has infinite number of solution if ? ??1
and ? =13
(2) System is inconsistent if ? ? ? ?1 and ? ? 13
(3) System is consistent if ? ?? ?1 and ? ?? 13
(4) System has unique solution if ? ?? ?1 and ? ? 13
Ans. (4)
Sol. ??
?
2
1 1 1
1 2 0
13
? 2 ?
2
– ? – 1 = 0
1
1,
2
? ? ?
? ? ? ? ?
??
2
1 1 5
2 9 0 13
3
Infinite solution ? = 1 & ? = 13
For unique sol
n
? ? ? 1
For no sol
n
? = 1 & ? ? 13
If ? ? 1 and ? ?? 13
Considering the case when
1
2
? ? ? and 13 ?? this
will generate no solution case
2. For
? ??
? ? ?
??
??
, 0,
2
, let ? ? ? ? ? ? ? 3sin( ) 2sin( ) and a
real number k be such that ? ? ? tan k tan . Then the
value of k is equal to :
(1) ?
2
3
(2) –5
(3)
2
3
(4) 5
Ans. (2 )
Sol. 3sin ? cos ? + 3sin ? cos ?
= 2sin ? cos ? – 2sin ? cos ?
5sin ? cos ? = –sin ? cos ?
? ? ? ?
1
tan tan
5
tan ? = –5tan ?
3. Let A( ?, 0) and B(0, ?) be the points on the line
5x + 7y = 50. Let the point P divide the line
segment AB internally in the ratio 7 : 3. Let 3x –
25 = 0 be a directrix of the ellipse ??
22
22
xy
E : 1
ab
and the corresponding focus be S. If from S, the
perpendicular on the x-axis passes through P, then
the length of the latus rectum of E is equal to
(1)
25
3
(2)
32
9
(3)
25
9
(4)
32
5
Ans. (4 )
Sol.
A (10, 0)
P (3, 5)
50
B 0,
7
? ?
?
?
? ??
?
?? ?
?? ?
x =
S
25
3
ae = 3
?
a 25
e3
a = 5
b = 4
2
2b 32
Length of LR
a5
??
Page 2
SECTION-A
1. Consider the system of linear equations
x + y + z = 5, x + 2y + ?
2
z = 9,
x + 3y + ?z = ?, where ?, ? ? R. Then, which of
the following statement is NOT correct?
(1) System has infinite number of solution if ? ??1
and ? =13
(2) System is inconsistent if ? ? ? ?1 and ? ? 13
(3) System is consistent if ? ?? ?1 and ? ?? 13
(4) System has unique solution if ? ?? ?1 and ? ? 13
Ans. (4)
Sol. ??
?
2
1 1 1
1 2 0
13
? 2 ?
2
– ? – 1 = 0
1
1,
2
? ? ?
? ? ? ? ?
??
2
1 1 5
2 9 0 13
3
Infinite solution ? = 1 & ? = 13
For unique sol
n
? ? ? 1
For no sol
n
? = 1 & ? ? 13
If ? ? 1 and ? ?? 13
Considering the case when
1
2
? ? ? and 13 ?? this
will generate no solution case
2. For
? ??
? ? ?
??
??
, 0,
2
, let ? ? ? ? ? ? ? 3sin( ) 2sin( ) and a
real number k be such that ? ? ? tan k tan . Then the
value of k is equal to :
(1) ?
2
3
(2) –5
(3)
2
3
(4) 5
Ans. (2 )
Sol. 3sin ? cos ? + 3sin ? cos ?
= 2sin ? cos ? – 2sin ? cos ?
5sin ? cos ? = –sin ? cos ?
? ? ? ?
1
tan tan
5
tan ? = –5tan ?
3. Let A( ?, 0) and B(0, ?) be the points on the line
5x + 7y = 50. Let the point P divide the line
segment AB internally in the ratio 7 : 3. Let 3x –
25 = 0 be a directrix of the ellipse ??
22
22
xy
E : 1
ab
and the corresponding focus be S. If from S, the
perpendicular on the x-axis passes through P, then
the length of the latus rectum of E is equal to
(1)
25
3
(2)
32
9
(3)
25
9
(4)
32
5
Ans. (4 )
Sol.
A (10, 0)
P (3, 5)
50
B 0,
7
? ?
?
?
? ??
?
?? ?
?? ?
x =
S
25
3
ae = 3
?
a 25
e3
a = 5
b = 4
2
2b 32
Length of LR
a5
??
4. Let ? ? ? ? ? ? ? ?
ˆˆ ˆ
a i j k, , R . Let a vector b be such
that the angle between a and b is
?
4
and
2
b6 ? ,
If ? a.b 3 2 , then the value of
? ?
? ? ? ?
2
22
ab is
equal to
(1) 90 (2) 75
(3) 95 (4) 85
Ans. (1)
Sol.
?
?
2
| b | 6 ;
??
?? | a || b | cos 3 2
2 2 2
| a | | b | cos 18
??
??
2
| a | 6
?
?
Also 1 + ?
2
+ ?
2
= 6
?
2
+ ?
2
= 5
to find
( ?
2
+ ?
2
)
2 2 2
| a | | b | sin
??
?
=
??
??
??
1
(5)(6)(6)
2
= 90
5. Let ? ? ? ? ?
23
f(x) (x 3) (x 2) ,x [ 4, 4] . If M and m are
the maximum and minimum values of f,
respectively in [–4, 4], then the value of M – m is :
(1) 600 (2) 392
(3) 608 (4) 108
Ans. (3)
Sol. f'(x) = (x + 3)
2
. 3(x – 2)
2
+ (x –2)
3
2(x + 3)
= 5(x + 3) (x – 2)
2
(x + 1)
f'(x) = 0, x = –3, –1, 2
–3 –1 2
+ – + +
f(–4) = –216
f(–3) = 0, f(4) = 49 × 8 = 392
M = 392, m = –216
M – m = 392 + 216 = 608
Ans = '3'
6. Let a and b be be two distinct positive real
numbers. Let 11
th
term of a GP, whose first term is
a and third term is b, is equal to p
th
term of another
GP, whose first term is a and fifth term is b. Then p
is equal to
(1) 20 (2) 25
(3) 21 (4) 24
Ans. (3)
Sol. 1
st
GP ? t
1
= a, t
3
= b = ar
2
? r
2
=
b
a
t
11
= ar
10
= a(r
2
)
5
=
??
?
??
??
5
b
a
a
2
nd
G.P. ? T
1
= a, T
5
= ar
4
= b
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
1/4
4
bb
rr
aa
T
p
= ar
p –1
p1
4
b
a
a
?
??
?
??
??
p1
5
4
11 p
bb
t T a a
aa
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
?
p1
5 p 21
4
?
? ? ?
7. If x
2
– y
2
+ 2hxy + 2gx + 2fy + c = 0 is the locus of
a point, which moves such that it is always
equidistant from the lines x + 2y + 7 = 0 and 2x – y
+ 8 = 0, then the value of g + c + h – f equals
(1) 14 (2) 6
(3) 8 (4) 29
Ans. (1)
Sol. Cocus of point P(x, y) whose distance from
Gives
X + 2y + 7 = 0 & 2x – y + 8 = 0 are equal is
? ? ? ?
??
x 2y 7 2x y 8
55
(x + 2y + 7)
2
–
(2x – y + 8)
2
= 0
Page 3
SECTION-A
1. Consider the system of linear equations
x + y + z = 5, x + 2y + ?
2
z = 9,
x + 3y + ?z = ?, where ?, ? ? R. Then, which of
the following statement is NOT correct?
(1) System has infinite number of solution if ? ??1
and ? =13
(2) System is inconsistent if ? ? ? ?1 and ? ? 13
(3) System is consistent if ? ?? ?1 and ? ?? 13
(4) System has unique solution if ? ?? ?1 and ? ? 13
Ans. (4)
Sol. ??
?
2
1 1 1
1 2 0
13
? 2 ?
2
– ? – 1 = 0
1
1,
2
? ? ?
? ? ? ? ?
??
2
1 1 5
2 9 0 13
3
Infinite solution ? = 1 & ? = 13
For unique sol
n
? ? ? 1
For no sol
n
? = 1 & ? ? 13
If ? ? 1 and ? ?? 13
Considering the case when
1
2
? ? ? and 13 ?? this
will generate no solution case
2. For
? ??
? ? ?
??
??
, 0,
2
, let ? ? ? ? ? ? ? 3sin( ) 2sin( ) and a
real number k be such that ? ? ? tan k tan . Then the
value of k is equal to :
(1) ?
2
3
(2) –5
(3)
2
3
(4) 5
Ans. (2 )
Sol. 3sin ? cos ? + 3sin ? cos ?
= 2sin ? cos ? – 2sin ? cos ?
5sin ? cos ? = –sin ? cos ?
? ? ? ?
1
tan tan
5
tan ? = –5tan ?
3. Let A( ?, 0) and B(0, ?) be the points on the line
5x + 7y = 50. Let the point P divide the line
segment AB internally in the ratio 7 : 3. Let 3x –
25 = 0 be a directrix of the ellipse ??
22
22
xy
E : 1
ab
and the corresponding focus be S. If from S, the
perpendicular on the x-axis passes through P, then
the length of the latus rectum of E is equal to
(1)
25
3
(2)
32
9
(3)
25
9
(4)
32
5
Ans. (4 )
Sol.
A (10, 0)
P (3, 5)
50
B 0,
7
? ?
?
?
? ??
?
?? ?
?? ?
x =
S
25
3
ae = 3
?
a 25
e3
a = 5
b = 4
2
2b 32
Length of LR
a5
??
4. Let ? ? ? ? ? ? ? ?
ˆˆ ˆ
a i j k, , R . Let a vector b be such
that the angle between a and b is
?
4
and
2
b6 ? ,
If ? a.b 3 2 , then the value of
? ?
? ? ? ?
2
22
ab is
equal to
(1) 90 (2) 75
(3) 95 (4) 85
Ans. (1)
Sol.
?
?
2
| b | 6 ;
??
?? | a || b | cos 3 2
2 2 2
| a | | b | cos 18
??
??
2
| a | 6
?
?
Also 1 + ?
2
+ ?
2
= 6
?
2
+ ?
2
= 5
to find
( ?
2
+ ?
2
)
2 2 2
| a | | b | sin
??
?
=
??
??
??
1
(5)(6)(6)
2
= 90
5. Let ? ? ? ? ?
23
f(x) (x 3) (x 2) ,x [ 4, 4] . If M and m are
the maximum and minimum values of f,
respectively in [–4, 4], then the value of M – m is :
(1) 600 (2) 392
(3) 608 (4) 108
Ans. (3)
Sol. f'(x) = (x + 3)
2
. 3(x – 2)
2
+ (x –2)
3
2(x + 3)
= 5(x + 3) (x – 2)
2
(x + 1)
f'(x) = 0, x = –3, –1, 2
–3 –1 2
+ – + +
f(–4) = –216
f(–3) = 0, f(4) = 49 × 8 = 392
M = 392, m = –216
M – m = 392 + 216 = 608
Ans = '3'
6. Let a and b be be two distinct positive real
numbers. Let 11
th
term of a GP, whose first term is
a and third term is b, is equal to p
th
term of another
GP, whose first term is a and fifth term is b. Then p
is equal to
(1) 20 (2) 25
(3) 21 (4) 24
Ans. (3)
Sol. 1
st
GP ? t
1
= a, t
3
= b = ar
2
? r
2
=
b
a
t
11
= ar
10
= a(r
2
)
5
=
??
?
??
??
5
b
a
a
2
nd
G.P. ? T
1
= a, T
5
= ar
4
= b
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
1/4
4
bb
rr
aa
T
p
= ar
p –1
p1
4
b
a
a
?
??
?
??
??
p1
5
4
11 p
bb
t T a a
aa
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
?
p1
5 p 21
4
?
? ? ?
7. If x
2
– y
2
+ 2hxy + 2gx + 2fy + c = 0 is the locus of
a point, which moves such that it is always
equidistant from the lines x + 2y + 7 = 0 and 2x – y
+ 8 = 0, then the value of g + c + h – f equals
(1) 14 (2) 6
(3) 8 (4) 29
Ans. (1)
Sol. Cocus of point P(x, y) whose distance from
Gives
X + 2y + 7 = 0 & 2x – y + 8 = 0 are equal is
? ? ? ?
??
x 2y 7 2x y 8
55
(x + 2y + 7)
2
–
(2x – y + 8)
2
= 0
Combined equation of lines
(x – 3y + 1) (3x + y + 15) = 0
3x
2
– 3y
2
– 8xy + 18x – 44y + 15 = 0
x
2
– y
2
– ? ? ? ?
8 44
xy 6x y 5 0
33
x
2
– y
2
+ 2h xy + 2gx 2 + 2fy + c = 0
? ? ? ? ?
4 22
h , g 3, f , c 5
33
? ? ? ? ? ? ? ? ? ?
4 22
g c h f 3 5 8 6 14
33
8. Let a and b be two vectors such that
? ? ? | b | 1 and | b a | 2 . Then
2
(b a) b ?? is equal
to
(1) 3
(2) 5
(3) 1
(4) 4
Ans. (2)
Sol.
? ?
?
? ? ? | b | 1 & | b a | 2
? ? ? ? ? ?
? ? ? ?
? ? ? ? ? ?
? ? ? ?
? ? ? ?
b a b b b a 0
? ? ? ?? ?
? ? ? ? ?
2 2 2
(b a) b b a b
= 4 + 1 = 5
9. Let ? y f(x) be a thrice differentiable function in
(–5, 5). Let the tangents to the curve y=f(x) at
(1, f(1)) and (3, f(3)) make angles
?
6
and
?
4
,
respectively with positive x-axis. If
? ?
? ?
? ? ? ? ? ? ? ?
?
3
2
1
27 f (t) 1 f (t)dt 3 where ?, ? ?are
integers, then the value of ? + ? equals
(1) –14
(2) 26
(3) –16
(4) 36
Ans. (2)
Sol. y = f(x) ? ?
dy
f '(x)
dx
? ?
? ? ? ? ?
?
?
(1,f(1))
dy 1 1
f '(1) tan f '(1)
dx 6
33
(3,f(3))
dy
f '(3) tan 1 f '(3) 1
dx 4
? ?
? ? ? ? ?
?
?
? ?
? ?
? ? ? ? ?
?
3
2
1
27 f '(t) 1 f "(t)dt 3
? ?
? ?
??
?
3
2
1
I f '(t) 1 f "(t)dt
f'(t) = z ? f"(t) dt = dz
z = f'(3) = 1
z = f'(1) =
1
3
??
? ? ? ?
??
??
?
1
1 3
2
1/ 3 1/ 3
z
I (z 1)dz z
3
?? ??
? ? ? ? ?
?? ??
????
1 1 1 1
1
33
3 3 3
? ? ? ?
4 10 4 10
3
3 3 27
93
??
? ? ? ? ? ? ?
??
??
4 10
3 27 3 36 10 3
3 27
?= 36, ? = – 10
? + ? = 36 – 10 = 26
10. Let P be a point on the hyperbola ??
22
xy
H : 1
94
,
in the first quadrant such that the area of triangle
formed by P and the two foci of H is 2 13 . Then,
the square of the distance of P from the origin is
(1) 18
(2) 26
(3) 22
(4) 20
Ans. (3)
Page 4
SECTION-A
1. Consider the system of linear equations
x + y + z = 5, x + 2y + ?
2
z = 9,
x + 3y + ?z = ?, where ?, ? ? R. Then, which of
the following statement is NOT correct?
(1) System has infinite number of solution if ? ??1
and ? =13
(2) System is inconsistent if ? ? ? ?1 and ? ? 13
(3) System is consistent if ? ?? ?1 and ? ?? 13
(4) System has unique solution if ? ?? ?1 and ? ? 13
Ans. (4)
Sol. ??
?
2
1 1 1
1 2 0
13
? 2 ?
2
– ? – 1 = 0
1
1,
2
? ? ?
? ? ? ? ?
??
2
1 1 5
2 9 0 13
3
Infinite solution ? = 1 & ? = 13
For unique sol
n
? ? ? 1
For no sol
n
? = 1 & ? ? 13
If ? ? 1 and ? ?? 13
Considering the case when
1
2
? ? ? and 13 ?? this
will generate no solution case
2. For
? ??
? ? ?
??
??
, 0,
2
, let ? ? ? ? ? ? ? 3sin( ) 2sin( ) and a
real number k be such that ? ? ? tan k tan . Then the
value of k is equal to :
(1) ?
2
3
(2) –5
(3)
2
3
(4) 5
Ans. (2 )
Sol. 3sin ? cos ? + 3sin ? cos ?
= 2sin ? cos ? – 2sin ? cos ?
5sin ? cos ? = –sin ? cos ?
? ? ? ?
1
tan tan
5
tan ? = –5tan ?
3. Let A( ?, 0) and B(0, ?) be the points on the line
5x + 7y = 50. Let the point P divide the line
segment AB internally in the ratio 7 : 3. Let 3x –
25 = 0 be a directrix of the ellipse ??
22
22
xy
E : 1
ab
and the corresponding focus be S. If from S, the
perpendicular on the x-axis passes through P, then
the length of the latus rectum of E is equal to
(1)
25
3
(2)
32
9
(3)
25
9
(4)
32
5
Ans. (4 )
Sol.
A (10, 0)
P (3, 5)
50
B 0,
7
? ?
?
?
? ??
?
?? ?
?? ?
x =
S
25
3
ae = 3
?
a 25
e3
a = 5
b = 4
2
2b 32
Length of LR
a5
??
4. Let ? ? ? ? ? ? ? ?
ˆˆ ˆ
a i j k, , R . Let a vector b be such
that the angle between a and b is
?
4
and
2
b6 ? ,
If ? a.b 3 2 , then the value of
? ?
? ? ? ?
2
22
ab is
equal to
(1) 90 (2) 75
(3) 95 (4) 85
Ans. (1)
Sol.
?
?
2
| b | 6 ;
??
?? | a || b | cos 3 2
2 2 2
| a | | b | cos 18
??
??
2
| a | 6
?
?
Also 1 + ?
2
+ ?
2
= 6
?
2
+ ?
2
= 5
to find
( ?
2
+ ?
2
)
2 2 2
| a | | b | sin
??
?
=
??
??
??
1
(5)(6)(6)
2
= 90
5. Let ? ? ? ? ?
23
f(x) (x 3) (x 2) ,x [ 4, 4] . If M and m are
the maximum and minimum values of f,
respectively in [–4, 4], then the value of M – m is :
(1) 600 (2) 392
(3) 608 (4) 108
Ans. (3)
Sol. f'(x) = (x + 3)
2
. 3(x – 2)
2
+ (x –2)
3
2(x + 3)
= 5(x + 3) (x – 2)
2
(x + 1)
f'(x) = 0, x = –3, –1, 2
–3 –1 2
+ – + +
f(–4) = –216
f(–3) = 0, f(4) = 49 × 8 = 392
M = 392, m = –216
M – m = 392 + 216 = 608
Ans = '3'
6. Let a and b be be two distinct positive real
numbers. Let 11
th
term of a GP, whose first term is
a and third term is b, is equal to p
th
term of another
GP, whose first term is a and fifth term is b. Then p
is equal to
(1) 20 (2) 25
(3) 21 (4) 24
Ans. (3)
Sol. 1
st
GP ? t
1
= a, t
3
= b = ar
2
? r
2
=
b
a
t
11
= ar
10
= a(r
2
)
5
=
??
?
??
??
5
b
a
a
2
nd
G.P. ? T
1
= a, T
5
= ar
4
= b
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
1/4
4
bb
rr
aa
T
p
= ar
p –1
p1
4
b
a
a
?
??
?
??
??
p1
5
4
11 p
bb
t T a a
aa
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
?
p1
5 p 21
4
?
? ? ?
7. If x
2
– y
2
+ 2hxy + 2gx + 2fy + c = 0 is the locus of
a point, which moves such that it is always
equidistant from the lines x + 2y + 7 = 0 and 2x – y
+ 8 = 0, then the value of g + c + h – f equals
(1) 14 (2) 6
(3) 8 (4) 29
Ans. (1)
Sol. Cocus of point P(x, y) whose distance from
Gives
X + 2y + 7 = 0 & 2x – y + 8 = 0 are equal is
? ? ? ?
??
x 2y 7 2x y 8
55
(x + 2y + 7)
2
–
(2x – y + 8)
2
= 0
Combined equation of lines
(x – 3y + 1) (3x + y + 15) = 0
3x
2
– 3y
2
– 8xy + 18x – 44y + 15 = 0
x
2
– y
2
– ? ? ? ?
8 44
xy 6x y 5 0
33
x
2
– y
2
+ 2h xy + 2gx 2 + 2fy + c = 0
? ? ? ? ?
4 22
h , g 3, f , c 5
33
? ? ? ? ? ? ? ? ? ?
4 22
g c h f 3 5 8 6 14
33
8. Let a and b be two vectors such that
? ? ? | b | 1 and | b a | 2 . Then
2
(b a) b ?? is equal
to
(1) 3
(2) 5
(3) 1
(4) 4
Ans. (2)
Sol.
? ?
?
? ? ? | b | 1 & | b a | 2
? ? ? ? ? ?
? ? ? ?
? ? ? ? ? ?
? ? ? ?
? ? ? ?
b a b b b a 0
? ? ? ?? ?
? ? ? ? ?
2 2 2
(b a) b b a b
= 4 + 1 = 5
9. Let ? y f(x) be a thrice differentiable function in
(–5, 5). Let the tangents to the curve y=f(x) at
(1, f(1)) and (3, f(3)) make angles
?
6
and
?
4
,
respectively with positive x-axis. If
? ?
? ?
? ? ? ? ? ? ? ?
?
3
2
1
27 f (t) 1 f (t)dt 3 where ?, ? ?are
integers, then the value of ? + ? equals
(1) –14
(2) 26
(3) –16
(4) 36
Ans. (2)
Sol. y = f(x) ? ?
dy
f '(x)
dx
? ?
? ? ? ? ?
?
?
(1,f(1))
dy 1 1
f '(1) tan f '(1)
dx 6
33
(3,f(3))
dy
f '(3) tan 1 f '(3) 1
dx 4
? ?
? ? ? ? ?
?
?
? ?
? ?
? ? ? ? ?
?
3
2
1
27 f '(t) 1 f "(t)dt 3
? ?
? ?
??
?
3
2
1
I f '(t) 1 f "(t)dt
f'(t) = z ? f"(t) dt = dz
z = f'(3) = 1
z = f'(1) =
1
3
??
? ? ? ?
??
??
?
1
1 3
2
1/ 3 1/ 3
z
I (z 1)dz z
3
?? ??
? ? ? ? ?
?? ??
????
1 1 1 1
1
33
3 3 3
? ? ? ?
4 10 4 10
3
3 3 27
93
??
? ? ? ? ? ? ?
??
??
4 10
3 27 3 36 10 3
3 27
?= 36, ? = – 10
? + ? = 36 – 10 = 26
10. Let P be a point on the hyperbola ??
22
xy
H : 1
94
,
in the first quadrant such that the area of triangle
formed by P and the two foci of H is 2 13 . Then,
the square of the distance of P from the origin is
(1) 18
(2) 26
(3) 22
(4) 20
Ans. (3)
Sol.
y
p
O
s
1
s
2
x
( , ) ? ?
22
xy
1
94
??
a
2
= 9, b
2
= 4
2
2 2 2 2
2
b
b a (e 1) e 1
a
? ? ? ? ?
2
4 13
e1
99
? ? ?
12
13 13
e s s 2ae 2 3 2 13
33
? ? ? ? ? ? ?
Area of
1 2 1 2
1
PS S s s 2 13
2
? ? ? ? ? ?
1
(2 13) 2 13 2
2
? ? ? ? ? ? ? ?
2 2 2
2
1 1 1 18 3 2
9 4 9
? ? ?
? ? ? ? ? ? ? ? ? ? ?
Distance of P from origin =
22
? ? ?
= 18 4 22 ??
11. Bag A contains 3 white, 7 red balls and bag B
contains 3 white, 2 red balls. One bag is selected at
random and a ball is drawn from it. The probability
of drawing the ball from the bag A, if the ball
drawn in white, is :
(1)
1
4
(2)
1
9
(3)
1
3
(4)
3
10
Ans. (3)
Sol. E
1
: A is selected
A
3W
7R
B
3W
2R
E
2
: B is selected
E : white ball is drawn
P (E
1
/E) =
?
?
?
?
? ? ?
1
1 1 2 2
1
P(E).P(E / E )
2 10
1 3 1 3
P(E ). P(E / E ) P(E ). P(E / E )
2 10 2 5
= ?
?
31
3 6 3
12. Let f : R ? R be defined ? ? ?
2x x
f(x) ae be cx . If
?? f(0) 1 , ? ?
e
f (log 2) 21 and
? ?
e
log 4
0
39
f(x) cx dx
2
??
?
, then the value of |a+b+c|
equals :
(1) 16 (2) 10
(3) 12 (4) 8
Ans. (4)
Sol. f(x) = ae
2x
+ be
x
+ cx f(0) = –1
a + b = –1
f ?(x) = 2ae
2x
+ be
x
+ c f ? (ln 2) = 21
8a + 2 b + c = 21
??
?
ln 4
2x x
0
39
(ae be )dx
2
??
??
??
??
ln 4
2x
x
0
ae 39
be
22
? 8a + 4b – ??
a 39
b
22
15a + 6b = 39
15 a – 6a – 6 = 39
9a = 45 ? a = 5
b = - 6
c = 21 – 40 + 12 = –7
a + b + c – 8
|a + b + c| = 8
Page 5
SECTION-A
1. Consider the system of linear equations
x + y + z = 5, x + 2y + ?
2
z = 9,
x + 3y + ?z = ?, where ?, ? ? R. Then, which of
the following statement is NOT correct?
(1) System has infinite number of solution if ? ??1
and ? =13
(2) System is inconsistent if ? ? ? ?1 and ? ? 13
(3) System is consistent if ? ?? ?1 and ? ?? 13
(4) System has unique solution if ? ?? ?1 and ? ? 13
Ans. (4)
Sol. ??
?
2
1 1 1
1 2 0
13
? 2 ?
2
– ? – 1 = 0
1
1,
2
? ? ?
? ? ? ? ?
??
2
1 1 5
2 9 0 13
3
Infinite solution ? = 1 & ? = 13
For unique sol
n
? ? ? 1
For no sol
n
? = 1 & ? ? 13
If ? ? 1 and ? ?? 13
Considering the case when
1
2
? ? ? and 13 ?? this
will generate no solution case
2. For
? ??
? ? ?
??
??
, 0,
2
, let ? ? ? ? ? ? ? 3sin( ) 2sin( ) and a
real number k be such that ? ? ? tan k tan . Then the
value of k is equal to :
(1) ?
2
3
(2) –5
(3)
2
3
(4) 5
Ans. (2 )
Sol. 3sin ? cos ? + 3sin ? cos ?
= 2sin ? cos ? – 2sin ? cos ?
5sin ? cos ? = –sin ? cos ?
? ? ? ?
1
tan tan
5
tan ? = –5tan ?
3. Let A( ?, 0) and B(0, ?) be the points on the line
5x + 7y = 50. Let the point P divide the line
segment AB internally in the ratio 7 : 3. Let 3x –
25 = 0 be a directrix of the ellipse ??
22
22
xy
E : 1
ab
and the corresponding focus be S. If from S, the
perpendicular on the x-axis passes through P, then
the length of the latus rectum of E is equal to
(1)
25
3
(2)
32
9
(3)
25
9
(4)
32
5
Ans. (4 )
Sol.
A (10, 0)
P (3, 5)
50
B 0,
7
? ?
?
?
? ??
?
?? ?
?? ?
x =
S
25
3
ae = 3
?
a 25
e3
a = 5
b = 4
2
2b 32
Length of LR
a5
??
4. Let ? ? ? ? ? ? ? ?
ˆˆ ˆ
a i j k, , R . Let a vector b be such
that the angle between a and b is
?
4
and
2
b6 ? ,
If ? a.b 3 2 , then the value of
? ?
? ? ? ?
2
22
ab is
equal to
(1) 90 (2) 75
(3) 95 (4) 85
Ans. (1)
Sol.
?
?
2
| b | 6 ;
??
?? | a || b | cos 3 2
2 2 2
| a | | b | cos 18
??
??
2
| a | 6
?
?
Also 1 + ?
2
+ ?
2
= 6
?
2
+ ?
2
= 5
to find
( ?
2
+ ?
2
)
2 2 2
| a | | b | sin
??
?
=
??
??
??
1
(5)(6)(6)
2
= 90
5. Let ? ? ? ? ?
23
f(x) (x 3) (x 2) ,x [ 4, 4] . If M and m are
the maximum and minimum values of f,
respectively in [–4, 4], then the value of M – m is :
(1) 600 (2) 392
(3) 608 (4) 108
Ans. (3)
Sol. f'(x) = (x + 3)
2
. 3(x – 2)
2
+ (x –2)
3
2(x + 3)
= 5(x + 3) (x – 2)
2
(x + 1)
f'(x) = 0, x = –3, –1, 2
–3 –1 2
+ – + +
f(–4) = –216
f(–3) = 0, f(4) = 49 × 8 = 392
M = 392, m = –216
M – m = 392 + 216 = 608
Ans = '3'
6. Let a and b be be two distinct positive real
numbers. Let 11
th
term of a GP, whose first term is
a and third term is b, is equal to p
th
term of another
GP, whose first term is a and fifth term is b. Then p
is equal to
(1) 20 (2) 25
(3) 21 (4) 24
Ans. (3)
Sol. 1
st
GP ? t
1
= a, t
3
= b = ar
2
? r
2
=
b
a
t
11
= ar
10
= a(r
2
)
5
=
??
?
??
??
5
b
a
a
2
nd
G.P. ? T
1
= a, T
5
= ar
4
= b
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
1/4
4
bb
rr
aa
T
p
= ar
p –1
p1
4
b
a
a
?
??
?
??
??
p1
5
4
11 p
bb
t T a a
aa
?
? ? ? ?
? ? ?
? ? ? ?
? ? ? ?
?
p1
5 p 21
4
?
? ? ?
7. If x
2
– y
2
+ 2hxy + 2gx + 2fy + c = 0 is the locus of
a point, which moves such that it is always
equidistant from the lines x + 2y + 7 = 0 and 2x – y
+ 8 = 0, then the value of g + c + h – f equals
(1) 14 (2) 6
(3) 8 (4) 29
Ans. (1)
Sol. Cocus of point P(x, y) whose distance from
Gives
X + 2y + 7 = 0 & 2x – y + 8 = 0 are equal is
? ? ? ?
??
x 2y 7 2x y 8
55
(x + 2y + 7)
2
–
(2x – y + 8)
2
= 0
Combined equation of lines
(x – 3y + 1) (3x + y + 15) = 0
3x
2
– 3y
2
– 8xy + 18x – 44y + 15 = 0
x
2
– y
2
– ? ? ? ?
8 44
xy 6x y 5 0
33
x
2
– y
2
+ 2h xy + 2gx 2 + 2fy + c = 0
? ? ? ? ?
4 22
h , g 3, f , c 5
33
? ? ? ? ? ? ? ? ? ?
4 22
g c h f 3 5 8 6 14
33
8. Let a and b be two vectors such that
? ? ? | b | 1 and | b a | 2 . Then
2
(b a) b ?? is equal
to
(1) 3
(2) 5
(3) 1
(4) 4
Ans. (2)
Sol.
? ?
?
? ? ? | b | 1 & | b a | 2
? ? ? ? ? ?
? ? ? ?
? ? ? ? ? ?
? ? ? ?
? ? ? ?
b a b b b a 0
? ? ? ?? ?
? ? ? ? ?
2 2 2
(b a) b b a b
= 4 + 1 = 5
9. Let ? y f(x) be a thrice differentiable function in
(–5, 5). Let the tangents to the curve y=f(x) at
(1, f(1)) and (3, f(3)) make angles
?
6
and
?
4
,
respectively with positive x-axis. If
? ?
? ?
? ? ? ? ? ? ? ?
?
3
2
1
27 f (t) 1 f (t)dt 3 where ?, ? ?are
integers, then the value of ? + ? equals
(1) –14
(2) 26
(3) –16
(4) 36
Ans. (2)
Sol. y = f(x) ? ?
dy
f '(x)
dx
? ?
? ? ? ? ?
?
?
(1,f(1))
dy 1 1
f '(1) tan f '(1)
dx 6
33
(3,f(3))
dy
f '(3) tan 1 f '(3) 1
dx 4
? ?
? ? ? ? ?
?
?
? ?
? ?
? ? ? ? ?
?
3
2
1
27 f '(t) 1 f "(t)dt 3
? ?
? ?
??
?
3
2
1
I f '(t) 1 f "(t)dt
f'(t) = z ? f"(t) dt = dz
z = f'(3) = 1
z = f'(1) =
1
3
??
? ? ? ?
??
??
?
1
1 3
2
1/ 3 1/ 3
z
I (z 1)dz z
3
?? ??
? ? ? ? ?
?? ??
????
1 1 1 1
1
33
3 3 3
? ? ? ?
4 10 4 10
3
3 3 27
93
??
? ? ? ? ? ? ?
??
??
4 10
3 27 3 36 10 3
3 27
?= 36, ? = – 10
? + ? = 36 – 10 = 26
10. Let P be a point on the hyperbola ??
22
xy
H : 1
94
,
in the first quadrant such that the area of triangle
formed by P and the two foci of H is 2 13 . Then,
the square of the distance of P from the origin is
(1) 18
(2) 26
(3) 22
(4) 20
Ans. (3)
Sol.
y
p
O
s
1
s
2
x
( , ) ? ?
22
xy
1
94
??
a
2
= 9, b
2
= 4
2
2 2 2 2
2
b
b a (e 1) e 1
a
? ? ? ? ?
2
4 13
e1
99
? ? ?
12
13 13
e s s 2ae 2 3 2 13
33
? ? ? ? ? ? ?
Area of
1 2 1 2
1
PS S s s 2 13
2
? ? ? ? ? ?
1
(2 13) 2 13 2
2
? ? ? ? ? ? ? ?
2 2 2
2
1 1 1 18 3 2
9 4 9
? ? ?
? ? ? ? ? ? ? ? ? ? ?
Distance of P from origin =
22
? ? ?
= 18 4 22 ??
11. Bag A contains 3 white, 7 red balls and bag B
contains 3 white, 2 red balls. One bag is selected at
random and a ball is drawn from it. The probability
of drawing the ball from the bag A, if the ball
drawn in white, is :
(1)
1
4
(2)
1
9
(3)
1
3
(4)
3
10
Ans. (3)
Sol. E
1
: A is selected
A
3W
7R
B
3W
2R
E
2
: B is selected
E : white ball is drawn
P (E
1
/E) =
?
?
?
?
? ? ?
1
1 1 2 2
1
P(E).P(E / E )
2 10
1 3 1 3
P(E ). P(E / E ) P(E ). P(E / E )
2 10 2 5
= ?
?
31
3 6 3
12. Let f : R ? R be defined ? ? ?
2x x
f(x) ae be cx . If
?? f(0) 1 , ? ?
e
f (log 2) 21 and
? ?
e
log 4
0
39
f(x) cx dx
2
??
?
, then the value of |a+b+c|
equals :
(1) 16 (2) 10
(3) 12 (4) 8
Ans. (4)
Sol. f(x) = ae
2x
+ be
x
+ cx f(0) = –1
a + b = –1
f ?(x) = 2ae
2x
+ be
x
+ c f ? (ln 2) = 21
8a + 2 b + c = 21
??
?
ln 4
2x x
0
39
(ae be )dx
2
??
??
??
??
ln 4
2x
x
0
ae 39
be
22
? 8a + 4b – ??
a 39
b
22
15a + 6b = 39
15 a – 6a – 6 = 39
9a = 45 ? a = 5
b = - 6
c = 21 – 40 + 12 = –7
a + b + c – 8
|a + b + c| = 8
13. Let ? ? ? ? ? ? ? ??
1
ˆ ˆ ˆ ˆ ˆˆ
L : r (i j 2k) (i j 2k), R
? ? ? ? ? ? ? ?
2
ˆ ˆ ˆ ˆˆ
L : r ( j k) (3i j pk), R and
? ? ? ? ? ?
3
ˆˆ ˆ
L : r ( i mj nk) R
Be three lines such that L
1
is perpendicular to L
2
and L
3
is perpendicular to both L
1
and L
2
. Then the
point which lies on L
3
is
(1) (–1, 7, 4) (2) (–1, –7, 4)
(3) (1, 7, –4) (4) (1, –7, 4)
Ans. (1)
Sol. L
1
? L
2
L
3
? L
1
, L
2
3 – 1 + 2 P = 0
P = – 1
? ? ? ? ?
?
ˆˆ ˆ
i j k
ˆˆ ˆ
1 1 2 i 7j 4k
3 1 1
( , 7 , 4 ) ? ? ? ? ? will lie on L
3
For ? = 1 the point will be (-1, 7, 4)
14. Let a and b be real constants such that the function
f defined by
? ? ? ?
?
?
??
?
2
x 3x a , x 1
f(x)
bx 2 , x 1
be
differentiable on R. Then, the value of
?
?
2
2
f(x)dx
equals
(1)
15
6
(2)
19
6
(3) 21 (4) 17
Ans. (4)
Sol. f is continuous f ?(x) = 2x + 3 , k < 1
? 4 + a = b + 2 b , x > 1
a = b – 2 f is differentiable
? b = 5
? a = 3
?
? ? ? ?
??
12
2
21
(x 3x 3)dx (5x 2)dx
=
?
? ? ? ?
? ? ? ?
? ? ? ?
? ? ? ?
12
3 2 2
21
x 3x 5x
3x 2x
3 2 2
=
? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ?
? ? ? ? ? ?
? ? ? ? ? ?
1 3 8 5
3 6 6 10 4 2
3 2 3 2
= ? ? ? ?
35
6 12 17
22
15. Let ?? f : {0} be a function satisfying
??
?
??
??
x f(x)
f
y f(y)
for all x, y, f(y) ? 0. If ? f (1) = 2024,
then
(1) xf ? (x) – 2024 f(x) = 0
(2) xf ?(x) + 2024f(x) = 0
(3) xf ?(x) +f(x) = 2024
(4) xf ?(x) –2023f(x) = 0
Ans. (1)
Sol.
x f(x)
f
y f(y)
??
?
??
??
f(1) 2024
f(1) 1
? ?
?
Partially differentiating w. r. t. x
x 1 1
f . f(x)
y y f(y)
??
?? ?
??
??
y ?x
?
? ?
1 f(x)
f(1).
x f(x)
2024f(x) = xf ?(x) ?? xf ?(x) – 2024 f(x) = 0
16. If z is a complex number, then the number of
common roots of the equation ? ? ?
1985 100
z z 1 0 and
? ? ? ?
32
z 2z 2z 1 0 , is equal to :
(1) 1 (2) 2
(3) 0 (4) 3
Ans. (2)
Sol. z
1985
+ z
100
+ 1 = 0 & z
3
+ 2z
2
+ 2z + 1 = 0
(z + 1) (z
2
– z + 1) + 2z(z + 1) = 0
(z + 1) (z
2
+ z + 1) = 0
? z = – 1 , z = w,
w
2
Now putting z = –1 not satisfy
Now put z = w
? w
1985
+ w
100
+ 1
? w
2
+ w + 1 = 0
? ?lso, z = w
2
? w
3970
+ w
200
+ 1
? w + w
2
+ 1 = 0
Two common root
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