Page 1
FINAL JEE –MAIN EXAMINATION – APRIL, 2024
(Held On Monday 08
th
April, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1. The value of k ?? ???? for which the integral
I
n
=
1
k n
0
(1 – x ) dx,
?? n ???@ ?? , satisfies 147 I
20
= 148 I
21
is :
(1) 10 (2) 8
(3) 14 (4) 7
Ans. (4)
Sol. I
n
=
1
k n
0
(1 x ) .1 dx ?M ?? I
n
= (1 – x
k
)
n
.x – nk
1
k n 1 k 1
0
(1 x ) .x .dx
?M?M
?M ?? I
n
= nk
1
k n k n 1
0
[(1 x ) (1 x ) ]dx
?M ?M ?M ?M ?? I
n
= nkI
n
– nkI
n
n
n 1
I nk
I nk 1
?M ?] ?K 21
20
I 21k
I 1 21k
?] ?K 147
148
?] ???@?@ k = 7
2. The sum of all the solutions of the equation
(8)
2x
– 16 ?? (8)
x
+ 48 = 0 is :
(1) 1 + log
6
(8) (2) log
8
(6)
(3) 1 + log
8
(6) (4) log
8
(4)
Ans. (3)
Sol. (8)
2x
– 16 ?? (8)
x
+ 48 = 0
Put 8
x
= t
t
2
– 16 + 48 = 0
?? t = 4 or t = 12
?? 8
x
= 4 8
x
= 12
?? x = log
8
x x = log
8
12
sum of solution = log
8
4 + log
8
12
= log
8
48 = log
8
(6.8)
= 1 + log
8
6
3. Let the circles C
1
: (x – ?? )
2
+ (y – ?? )
2
=
2
1
r and
C
2
: (x – 8)
2
+
2
15
y
2
????
?M????
????
=
2
2
r touch each other
externally at the point (6, 6). If the point (6, 6)
divides the line segment joining the centres of the
circles C
1
and C
2
internally in the ratio 2 : 1, then
( ?? + ?? ) + 4
?H ?I 2 2
1 2
r r ?K equals
(1) 110 (2) 130
(3) 125 (4) 145
Ans. (2)
Sol.
r
1
r
2
C
2
C
1
( ?? ?L?? )
P
2 : 1
C
2
( ?? ?L ?? ) C
1 P
(6, 6)
16
6
3
?K??
?] and
15
6
3
?K??
?] ?? ( ?? , ?? ) ?? (2, 3)
Also, C
1
C
2
= r
1
+
r
2
???@
2
2
2 2
15
(2 8) 3 2r r
2
????
?M ?K ?M ?] ?K ????
????
?? r
2
=
5
2
?? r
1
= 2r
2
= 5
?| ( ?? ?@?K ?@ ?? ) + 4
2 2
1 2
(r r ) ?K = 5 + 4
25
25
4
????
?K ????
????
= 130 ?@
Page 2
FINAL JEE –MAIN EXAMINATION – APRIL, 2024
(Held On Monday 08
th
April, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1. The value of k ?? ???? for which the integral
I
n
=
1
k n
0
(1 – x ) dx,
?? n ???@ ?? , satisfies 147 I
20
= 148 I
21
is :
(1) 10 (2) 8
(3) 14 (4) 7
Ans. (4)
Sol. I
n
=
1
k n
0
(1 x ) .1 dx ?M ?? I
n
= (1 – x
k
)
n
.x – nk
1
k n 1 k 1
0
(1 x ) .x .dx
?M?M
?M ?? I
n
= nk
1
k n k n 1
0
[(1 x ) (1 x ) ]dx
?M ?M ?M ?M ?? I
n
= nkI
n
– nkI
n
n
n 1
I nk
I nk 1
?M ?] ?K 21
20
I 21k
I 1 21k
?] ?K 147
148
?] ???@?@ k = 7
2. The sum of all the solutions of the equation
(8)
2x
– 16 ?? (8)
x
+ 48 = 0 is :
(1) 1 + log
6
(8) (2) log
8
(6)
(3) 1 + log
8
(6) (4) log
8
(4)
Ans. (3)
Sol. (8)
2x
– 16 ?? (8)
x
+ 48 = 0
Put 8
x
= t
t
2
– 16 + 48 = 0
?? t = 4 or t = 12
?? 8
x
= 4 8
x
= 12
?? x = log
8
x x = log
8
12
sum of solution = log
8
4 + log
8
12
= log
8
48 = log
8
(6.8)
= 1 + log
8
6
3. Let the circles C
1
: (x – ?? )
2
+ (y – ?? )
2
=
2
1
r and
C
2
: (x – 8)
2
+
2
15
y
2
????
?M????
????
=
2
2
r touch each other
externally at the point (6, 6). If the point (6, 6)
divides the line segment joining the centres of the
circles C
1
and C
2
internally in the ratio 2 : 1, then
( ?? + ?? ) + 4
?H ?I 2 2
1 2
r r ?K equals
(1) 110 (2) 130
(3) 125 (4) 145
Ans. (2)
Sol.
r
1
r
2
C
2
C
1
( ?? ?L?? )
P
2 : 1
C
2
( ?? ?L ?? ) C
1 P
(6, 6)
16
6
3
?K??
?] and
15
6
3
?K??
?] ?? ( ?? , ?? ) ?? (2, 3)
Also, C
1
C
2
= r
1
+
r
2
???@
2
2
2 2
15
(2 8) 3 2r r
2
????
?M ?K ?M ?] ?K ????
????
?? r
2
=
5
2
?? r
1
= 2r
2
= 5
?| ( ?? ?@?K ?@ ?? ) + 4
2 2
1 2
(r r ) ?K = 5 + 4
25
25
4
????
?K ????
????
= 130 ?@ 4. Let P(x, y, z) be a point in the first octant, whose
projection in the xy-plane is the point Q. Let
OP = ?? ; the angle between OQ and the positive
x-axis be ?? ; and the angle between OP and the
positive z-axis be ?? , where O is the origin. Then
the distance of P from the x-axis is :
(1)
2 2
1 sin cos ?? ?M ?? ?? (2)
2 2
1 cos sin ?? ?K ?? ??
(3)
2 2
1 sin cos ?? ?M ?? ?? (4)
2 2
1 cos sin ?? ?K ?? ??
Ans. (1)
Sol. P(x, y, z), Q(x, y, O) ; x
2
+ y
2
+ z
2
= ?? 2
ˆˆ
OQ xi yj ?]?K
cos ?? =
2 2
x
x y ?K
cos ?? =
2 2 2
z
x y z ?K?K
???@ sin
2
???@ =
2 2
2 2 2
x y
x y z
?K ?K?K
distance of P from x-axis
2 2
y z ?K
???@
2 2
x ???M ???@
2
2
x
1 ???M
??
=
2 2
1 cos sin ?? ?M ?? ?? ?@
5. The number of critical points of the function
f(x) = (x – 2)
2/3
(2x + 1) is :
(1) 2 (2) 0
(3) 1 (4) 3
Ans. (1)
Sol. f(x) = (x – 2)
2/3
(2x + 1)
f'(x) =
2
3
(x – 2)
–1/3
(2x + 1) + (x – 2)
2/3
(2)
f'(x) = 2 ×
1/3
(2x 1) (x 2)
3(x 2)
?K ?K ?M ?M
1/3
3x 1
0
(x 2)
?M ?] ?M
Critical points x =
1
3
and x = 2
6. Let f(x) be a positive function such that the area
bounded by y = f(x), y = 0 from x = 0 to x = a > 0
is e
–a
+ 4a
2
+ a – 1. Then the differential equation,
whose general solution is y = c
1
f(x) + c
2
, where c
1
and c
2
are arbitrary constants, is :
(1)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?K ?]
(2)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?M ?]
(3)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
(4)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?M ?]
Ans. (3)
Sol.
a
a 2
0
f(x)dx e 4a a 1
?M ?] ?K ?K ?M ??
f(a) = –e
–a
+ 8a + 1
f(x) = –e
–x
+ 8x + 1
Now y = C
1
f(x) + C
2
1
dy
C f '(x)
dx
?] = C
1
(e
–x
+ 8) …..(1)
2
2
d y
dx
= –C
1
e
–x
?? –e
x
2
2
d y
dx
Put in equation (1)
2
x x
2
dy d y
e (e 8)
dx dx
?M ?] ?M ?K
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
Page 3
FINAL JEE –MAIN EXAMINATION – APRIL, 2024
(Held On Monday 08
th
April, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1. The value of k ?? ???? for which the integral
I
n
=
1
k n
0
(1 – x ) dx,
?? n ???@ ?? , satisfies 147 I
20
= 148 I
21
is :
(1) 10 (2) 8
(3) 14 (4) 7
Ans. (4)
Sol. I
n
=
1
k n
0
(1 x ) .1 dx ?M ?? I
n
= (1 – x
k
)
n
.x – nk
1
k n 1 k 1
0
(1 x ) .x .dx
?M?M
?M ?? I
n
= nk
1
k n k n 1
0
[(1 x ) (1 x ) ]dx
?M ?M ?M ?M ?? I
n
= nkI
n
– nkI
n
n
n 1
I nk
I nk 1
?M ?] ?K 21
20
I 21k
I 1 21k
?] ?K 147
148
?] ???@?@ k = 7
2. The sum of all the solutions of the equation
(8)
2x
– 16 ?? (8)
x
+ 48 = 0 is :
(1) 1 + log
6
(8) (2) log
8
(6)
(3) 1 + log
8
(6) (4) log
8
(4)
Ans. (3)
Sol. (8)
2x
– 16 ?? (8)
x
+ 48 = 0
Put 8
x
= t
t
2
– 16 + 48 = 0
?? t = 4 or t = 12
?? 8
x
= 4 8
x
= 12
?? x = log
8
x x = log
8
12
sum of solution = log
8
4 + log
8
12
= log
8
48 = log
8
(6.8)
= 1 + log
8
6
3. Let the circles C
1
: (x – ?? )
2
+ (y – ?? )
2
=
2
1
r and
C
2
: (x – 8)
2
+
2
15
y
2
????
?M????
????
=
2
2
r touch each other
externally at the point (6, 6). If the point (6, 6)
divides the line segment joining the centres of the
circles C
1
and C
2
internally in the ratio 2 : 1, then
( ?? + ?? ) + 4
?H ?I 2 2
1 2
r r ?K equals
(1) 110 (2) 130
(3) 125 (4) 145
Ans. (2)
Sol.
r
1
r
2
C
2
C
1
( ?? ?L?? )
P
2 : 1
C
2
( ?? ?L ?? ) C
1 P
(6, 6)
16
6
3
?K??
?] and
15
6
3
?K??
?] ?? ( ?? , ?? ) ?? (2, 3)
Also, C
1
C
2
= r
1
+
r
2
???@
2
2
2 2
15
(2 8) 3 2r r
2
????
?M ?K ?M ?] ?K ????
????
?? r
2
=
5
2
?? r
1
= 2r
2
= 5
?| ( ?? ?@?K ?@ ?? ) + 4
2 2
1 2
(r r ) ?K = 5 + 4
25
25
4
????
?K ????
????
= 130 ?@ 4. Let P(x, y, z) be a point in the first octant, whose
projection in the xy-plane is the point Q. Let
OP = ?? ; the angle between OQ and the positive
x-axis be ?? ; and the angle between OP and the
positive z-axis be ?? , where O is the origin. Then
the distance of P from the x-axis is :
(1)
2 2
1 sin cos ?? ?M ?? ?? (2)
2 2
1 cos sin ?? ?K ?? ??
(3)
2 2
1 sin cos ?? ?M ?? ?? (4)
2 2
1 cos sin ?? ?K ?? ??
Ans. (1)
Sol. P(x, y, z), Q(x, y, O) ; x
2
+ y
2
+ z
2
= ?? 2
ˆˆ
OQ xi yj ?]?K
cos ?? =
2 2
x
x y ?K
cos ?? =
2 2 2
z
x y z ?K?K
???@ sin
2
???@ =
2 2
2 2 2
x y
x y z
?K ?K?K
distance of P from x-axis
2 2
y z ?K
???@
2 2
x ???M ???@
2
2
x
1 ???M
??
=
2 2
1 cos sin ?? ?M ?? ?? ?@
5. The number of critical points of the function
f(x) = (x – 2)
2/3
(2x + 1) is :
(1) 2 (2) 0
(3) 1 (4) 3
Ans. (1)
Sol. f(x) = (x – 2)
2/3
(2x + 1)
f'(x) =
2
3
(x – 2)
–1/3
(2x + 1) + (x – 2)
2/3
(2)
f'(x) = 2 ×
1/3
(2x 1) (x 2)
3(x 2)
?K ?K ?M ?M
1/3
3x 1
0
(x 2)
?M ?] ?M
Critical points x =
1
3
and x = 2
6. Let f(x) be a positive function such that the area
bounded by y = f(x), y = 0 from x = 0 to x = a > 0
is e
–a
+ 4a
2
+ a – 1. Then the differential equation,
whose general solution is y = c
1
f(x) + c
2
, where c
1
and c
2
are arbitrary constants, is :
(1)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?K ?]
(2)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?M ?]
(3)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
(4)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?M ?]
Ans. (3)
Sol.
a
a 2
0
f(x)dx e 4a a 1
?M ?] ?K ?K ?M ??
f(a) = –e
–a
+ 8a + 1
f(x) = –e
–x
+ 8x + 1
Now y = C
1
f(x) + C
2
1
dy
C f '(x)
dx
?] = C
1
(e
–x
+ 8) …..(1)
2
2
d y
dx
= –C
1
e
–x
?? –e
x
2
2
d y
dx
Put in equation (1)
2
x x
2
dy d y
e (e 8)
dx dx
?M ?] ?M ?K
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
7. Let f(x) = 4cos
3
x + 3 3 cos
2
x – 10. The number
of points of local maxima of f in interval (0, 2 ?? ) is:
(1) 1 (2) 2
(3) 3 (4) 4
Ans. (2)
Sol. f(x) = 4cos
3
(x) + 3 3 cos
2
(x) – 10 ; x ?? (0, 2 ?? )
???@ f'(x) = 12cos
2
x[–sin(x)] + 3 3 (2cos(x))[–sin(x)]
???@ f'(x) = –6sin(x) cos(x)[2cos(x) + 3 ]
–
+
–
+
–
+
–
2 ?? 0
local maxima at x =
5 7
,
6 6
????
8. Let A =
2 a 0
1 3 1
0 5 b
????
????
????
????
. If A
3
= 4A
2
– A – 21I, where
I is the identity matrix of order 3 × 3, then 2a + 3b
is equal to :
(1) –10 (2) –13
(3) –9 (4) –12
Ans. (2)
Sol. A
3
– 4A
2
+ A + 21 I = 0
tr(A) = 4 = 5 + 6 ???@ b = –1
|A| = –21
–16 + a = –21 ?? a = –5
2a + 3b = –13
9. If the shortest distance between the lines
1
ˆˆ ˆ
L : r (2 )i (1 3 )j (3 4 )k, ?] ?K ?? ?K ?M ?? ?K ?K ?? ?? ??
2
ˆˆ ˆ
L : r 2(1 )i 3(1 )j (5 )k, ?] ?K ?? ?K ?K ?? ?K ?K ?? ?? ??
is
m
n
, where gcd (m, n) = 1, then the value of
m + n equals.
(1) 384 (2) 387
(3) 377 (4) 390
Ans. (2)
Sol.
C
D
Shortes distance (CD) =
AB p q
| p q |
????
??
=
ˆ ˆ ˆ ˆ ˆˆ
(0i 2j 2k).( 15i 7j 9k)
355
?K ?K ?M ?K ?K
=
0 14 18
355
?K?K
=
32
355
?| m + n = 32 + 355 = 387
10. Let the sum of two positive integers be 24. If the
probability, that their product is not less than
3
4
times their greatest positive product, is
m
n
,
where gcd(m, n) = 1, then n – m equals :
(1) 9 (2) 11
(3) 8 (4) 10
Ans. (4)
Sol. x + y = 24, x, y ?? ?@ N
AM > GM ???@ xy ?? 144
xy ?? 108
Favorable pairs of (x, y) are
(13, 11), (12, 12), (14, 10), (15, 9), (16, 8),
(17, 7), (18, 6), (6, 18), (7, 17), (8, 16), (9, 15),
(10, 14), (11, 13)
i.e. 13 cases
Total choices for x + y = 24 is 23
Probability =
13 m
23 n
?]
n – m = 10
Page 4
FINAL JEE –MAIN EXAMINATION – APRIL, 2024
(Held On Monday 08
th
April, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1. The value of k ?? ???? for which the integral
I
n
=
1
k n
0
(1 – x ) dx,
?? n ???@ ?? , satisfies 147 I
20
= 148 I
21
is :
(1) 10 (2) 8
(3) 14 (4) 7
Ans. (4)
Sol. I
n
=
1
k n
0
(1 x ) .1 dx ?M ?? I
n
= (1 – x
k
)
n
.x – nk
1
k n 1 k 1
0
(1 x ) .x .dx
?M?M
?M ?? I
n
= nk
1
k n k n 1
0
[(1 x ) (1 x ) ]dx
?M ?M ?M ?M ?? I
n
= nkI
n
– nkI
n
n
n 1
I nk
I nk 1
?M ?] ?K 21
20
I 21k
I 1 21k
?] ?K 147
148
?] ???@?@ k = 7
2. The sum of all the solutions of the equation
(8)
2x
– 16 ?? (8)
x
+ 48 = 0 is :
(1) 1 + log
6
(8) (2) log
8
(6)
(3) 1 + log
8
(6) (4) log
8
(4)
Ans. (3)
Sol. (8)
2x
– 16 ?? (8)
x
+ 48 = 0
Put 8
x
= t
t
2
– 16 + 48 = 0
?? t = 4 or t = 12
?? 8
x
= 4 8
x
= 12
?? x = log
8
x x = log
8
12
sum of solution = log
8
4 + log
8
12
= log
8
48 = log
8
(6.8)
= 1 + log
8
6
3. Let the circles C
1
: (x – ?? )
2
+ (y – ?? )
2
=
2
1
r and
C
2
: (x – 8)
2
+
2
15
y
2
????
?M????
????
=
2
2
r touch each other
externally at the point (6, 6). If the point (6, 6)
divides the line segment joining the centres of the
circles C
1
and C
2
internally in the ratio 2 : 1, then
( ?? + ?? ) + 4
?H ?I 2 2
1 2
r r ?K equals
(1) 110 (2) 130
(3) 125 (4) 145
Ans. (2)
Sol.
r
1
r
2
C
2
C
1
( ?? ?L?? )
P
2 : 1
C
2
( ?? ?L ?? ) C
1 P
(6, 6)
16
6
3
?K??
?] and
15
6
3
?K??
?] ?? ( ?? , ?? ) ?? (2, 3)
Also, C
1
C
2
= r
1
+
r
2
???@
2
2
2 2
15
(2 8) 3 2r r
2
????
?M ?K ?M ?] ?K ????
????
?? r
2
=
5
2
?? r
1
= 2r
2
= 5
?| ( ?? ?@?K ?@ ?? ) + 4
2 2
1 2
(r r ) ?K = 5 + 4
25
25
4
????
?K ????
????
= 130 ?@ 4. Let P(x, y, z) be a point in the first octant, whose
projection in the xy-plane is the point Q. Let
OP = ?? ; the angle between OQ and the positive
x-axis be ?? ; and the angle between OP and the
positive z-axis be ?? , where O is the origin. Then
the distance of P from the x-axis is :
(1)
2 2
1 sin cos ?? ?M ?? ?? (2)
2 2
1 cos sin ?? ?K ?? ??
(3)
2 2
1 sin cos ?? ?M ?? ?? (4)
2 2
1 cos sin ?? ?K ?? ??
Ans. (1)
Sol. P(x, y, z), Q(x, y, O) ; x
2
+ y
2
+ z
2
= ?? 2
ˆˆ
OQ xi yj ?]?K
cos ?? =
2 2
x
x y ?K
cos ?? =
2 2 2
z
x y z ?K?K
???@ sin
2
???@ =
2 2
2 2 2
x y
x y z
?K ?K?K
distance of P from x-axis
2 2
y z ?K
???@
2 2
x ???M ???@
2
2
x
1 ???M
??
=
2 2
1 cos sin ?? ?M ?? ?? ?@
5. The number of critical points of the function
f(x) = (x – 2)
2/3
(2x + 1) is :
(1) 2 (2) 0
(3) 1 (4) 3
Ans. (1)
Sol. f(x) = (x – 2)
2/3
(2x + 1)
f'(x) =
2
3
(x – 2)
–1/3
(2x + 1) + (x – 2)
2/3
(2)
f'(x) = 2 ×
1/3
(2x 1) (x 2)
3(x 2)
?K ?K ?M ?M
1/3
3x 1
0
(x 2)
?M ?] ?M
Critical points x =
1
3
and x = 2
6. Let f(x) be a positive function such that the area
bounded by y = f(x), y = 0 from x = 0 to x = a > 0
is e
–a
+ 4a
2
+ a – 1. Then the differential equation,
whose general solution is y = c
1
f(x) + c
2
, where c
1
and c
2
are arbitrary constants, is :
(1)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?K ?]
(2)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?M ?]
(3)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
(4)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?M ?]
Ans. (3)
Sol.
a
a 2
0
f(x)dx e 4a a 1
?M ?] ?K ?K ?M ??
f(a) = –e
–a
+ 8a + 1
f(x) = –e
–x
+ 8x + 1
Now y = C
1
f(x) + C
2
1
dy
C f '(x)
dx
?] = C
1
(e
–x
+ 8) …..(1)
2
2
d y
dx
= –C
1
e
–x
?? –e
x
2
2
d y
dx
Put in equation (1)
2
x x
2
dy d y
e (e 8)
dx dx
?M ?] ?M ?K
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
7. Let f(x) = 4cos
3
x + 3 3 cos
2
x – 10. The number
of points of local maxima of f in interval (0, 2 ?? ) is:
(1) 1 (2) 2
(3) 3 (4) 4
Ans. (2)
Sol. f(x) = 4cos
3
(x) + 3 3 cos
2
(x) – 10 ; x ?? (0, 2 ?? )
???@ f'(x) = 12cos
2
x[–sin(x)] + 3 3 (2cos(x))[–sin(x)]
???@ f'(x) = –6sin(x) cos(x)[2cos(x) + 3 ]
–
+
–
+
–
+
–
2 ?? 0
local maxima at x =
5 7
,
6 6
????
8. Let A =
2 a 0
1 3 1
0 5 b
????
????
????
????
. If A
3
= 4A
2
– A – 21I, where
I is the identity matrix of order 3 × 3, then 2a + 3b
is equal to :
(1) –10 (2) –13
(3) –9 (4) –12
Ans. (2)
Sol. A
3
– 4A
2
+ A + 21 I = 0
tr(A) = 4 = 5 + 6 ???@ b = –1
|A| = –21
–16 + a = –21 ?? a = –5
2a + 3b = –13
9. If the shortest distance between the lines
1
ˆˆ ˆ
L : r (2 )i (1 3 )j (3 4 )k, ?] ?K ?? ?K ?M ?? ?K ?K ?? ?? ??
2
ˆˆ ˆ
L : r 2(1 )i 3(1 )j (5 )k, ?] ?K ?? ?K ?K ?? ?K ?K ?? ?? ??
is
m
n
, where gcd (m, n) = 1, then the value of
m + n equals.
(1) 384 (2) 387
(3) 377 (4) 390
Ans. (2)
Sol.
C
D
Shortes distance (CD) =
AB p q
| p q |
????
??
=
ˆ ˆ ˆ ˆ ˆˆ
(0i 2j 2k).( 15i 7j 9k)
355
?K ?K ?M ?K ?K
=
0 14 18
355
?K?K
=
32
355
?| m + n = 32 + 355 = 387
10. Let the sum of two positive integers be 24. If the
probability, that their product is not less than
3
4
times their greatest positive product, is
m
n
,
where gcd(m, n) = 1, then n – m equals :
(1) 9 (2) 11
(3) 8 (4) 10
Ans. (4)
Sol. x + y = 24, x, y ?? ?@ N
AM > GM ???@ xy ?? 144
xy ?? 108
Favorable pairs of (x, y) are
(13, 11), (12, 12), (14, 10), (15, 9), (16, 8),
(17, 7), (18, 6), (6, 18), (7, 17), (8, 16), (9, 15),
(10, 14), (11, 13)
i.e. 13 cases
Total choices for x + y = 24 is 23
Probability =
13 m
23 n
?]
n – m = 10
11. If sinx = –
3
5
, where ?? < x <
3
2
?? ,
then 80(tan
2
x – cosx) is equal to :
(1) 109 (2) 108
(3) 18 (4) 19
Ans. (1)
Sol. sinx =
3
5
?M , ?? < x <
3
2
??
tanx =
3
4
cosx =
4
5
?M
80(tan
2
x – cosx)
=
9 4
80
16 5
????
?K ????
????
= 45 + 64 = 109
12. Let I(x) =
2 2
6
dx
sin x(1 cot x) ?M ?? . If I(0) = 3, then
I
12
?? ????
????
????
is equal to :
(1) 3 (2) 3 3
(3) 6 3 (4) 2 3
Ans. (2)
Sol. I(x) =
2
2 2 2
6dx 6cosec xdx
sin x(1 cot x) (1 cot x)
?] ?M?M
????
Put 1 – cotx = t
cosec
2
x dx = dt
I =
2
6dt 6
c
t t
?M ?]?K
??
I(x) =
6
c
1 cot x
?M ?M , c = 3
I(x) =
6
3
1 cot x
?M ?M ,
6
I 3
12
1 (2 3)
?? ????
?]?M
????
?M?K ????
6 6( 3 1)
I 3 3 3 3 2
12 2
3 1
???M ????
?] ?K ?] ?K ?] ????
?K ????
13. The equations of two sides AB and AC of a
triangle ABC are 4x + y = 14 and 3x – 2y = 5,
respectively. The point
4
2,
3
????
?M ????
????
divides the third
side BC internally in the ratio 2 : 1. The equation
of the side BC is :
(1) x – 6y – 10 = 0 (2) x – 3y – 6 = 0
(3) x + 3y + 2 = 0 (4) x + 6y + 6 = 0
Ans. (3)
Sol.
3x –2y = 5
4x + y = 14
A
B (x
1
, 14 – 4x
1
) C
2 : 1
•
2 1
2x x
2
3
?K ?] ,
?H ?I 2
1
3x 5
2 14 4x
2
3
?M ????
?K?M
????
????
=
4
3
?M
2x
2
+ x
1
= 6, 3x
2
– 4x
1
= – 13
x
2
= 1, x
1
= 4
So, C(1, – 1) , B(4, –2)
m =
1
3
?M
Equation of BC : y + 1 =
1
3
?M (x – 1)
3y + 3 = – x + 1
x + 3y + 2 = 0
Page 5
FINAL JEE –MAIN EXAMINATION – APRIL, 2024
(Held On Monday 08
th
April, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1. The value of k ?? ???? for which the integral
I
n
=
1
k n
0
(1 – x ) dx,
?? n ???@ ?? , satisfies 147 I
20
= 148 I
21
is :
(1) 10 (2) 8
(3) 14 (4) 7
Ans. (4)
Sol. I
n
=
1
k n
0
(1 x ) .1 dx ?M ?? I
n
= (1 – x
k
)
n
.x – nk
1
k n 1 k 1
0
(1 x ) .x .dx
?M?M
?M ?? I
n
= nk
1
k n k n 1
0
[(1 x ) (1 x ) ]dx
?M ?M ?M ?M ?? I
n
= nkI
n
– nkI
n
n
n 1
I nk
I nk 1
?M ?] ?K 21
20
I 21k
I 1 21k
?] ?K 147
148
?] ???@?@ k = 7
2. The sum of all the solutions of the equation
(8)
2x
– 16 ?? (8)
x
+ 48 = 0 is :
(1) 1 + log
6
(8) (2) log
8
(6)
(3) 1 + log
8
(6) (4) log
8
(4)
Ans. (3)
Sol. (8)
2x
– 16 ?? (8)
x
+ 48 = 0
Put 8
x
= t
t
2
– 16 + 48 = 0
?? t = 4 or t = 12
?? 8
x
= 4 8
x
= 12
?? x = log
8
x x = log
8
12
sum of solution = log
8
4 + log
8
12
= log
8
48 = log
8
(6.8)
= 1 + log
8
6
3. Let the circles C
1
: (x – ?? )
2
+ (y – ?? )
2
=
2
1
r and
C
2
: (x – 8)
2
+
2
15
y
2
????
?M????
????
=
2
2
r touch each other
externally at the point (6, 6). If the point (6, 6)
divides the line segment joining the centres of the
circles C
1
and C
2
internally in the ratio 2 : 1, then
( ?? + ?? ) + 4
?H ?I 2 2
1 2
r r ?K equals
(1) 110 (2) 130
(3) 125 (4) 145
Ans. (2)
Sol.
r
1
r
2
C
2
C
1
( ?? ?L?? )
P
2 : 1
C
2
( ?? ?L ?? ) C
1 P
(6, 6)
16
6
3
?K??
?] and
15
6
3
?K??
?] ?? ( ?? , ?? ) ?? (2, 3)
Also, C
1
C
2
= r
1
+
r
2
???@
2
2
2 2
15
(2 8) 3 2r r
2
????
?M ?K ?M ?] ?K ????
????
?? r
2
=
5
2
?? r
1
= 2r
2
= 5
?| ( ?? ?@?K ?@ ?? ) + 4
2 2
1 2
(r r ) ?K = 5 + 4
25
25
4
????
?K ????
????
= 130 ?@ 4. Let P(x, y, z) be a point in the first octant, whose
projection in the xy-plane is the point Q. Let
OP = ?? ; the angle between OQ and the positive
x-axis be ?? ; and the angle between OP and the
positive z-axis be ?? , where O is the origin. Then
the distance of P from the x-axis is :
(1)
2 2
1 sin cos ?? ?M ?? ?? (2)
2 2
1 cos sin ?? ?K ?? ??
(3)
2 2
1 sin cos ?? ?M ?? ?? (4)
2 2
1 cos sin ?? ?K ?? ??
Ans. (1)
Sol. P(x, y, z), Q(x, y, O) ; x
2
+ y
2
+ z
2
= ?? 2
ˆˆ
OQ xi yj ?]?K
cos ?? =
2 2
x
x y ?K
cos ?? =
2 2 2
z
x y z ?K?K
???@ sin
2
???@ =
2 2
2 2 2
x y
x y z
?K ?K?K
distance of P from x-axis
2 2
y z ?K
???@
2 2
x ???M ???@
2
2
x
1 ???M
??
=
2 2
1 cos sin ?? ?M ?? ?? ?@
5. The number of critical points of the function
f(x) = (x – 2)
2/3
(2x + 1) is :
(1) 2 (2) 0
(3) 1 (4) 3
Ans. (1)
Sol. f(x) = (x – 2)
2/3
(2x + 1)
f'(x) =
2
3
(x – 2)
–1/3
(2x + 1) + (x – 2)
2/3
(2)
f'(x) = 2 ×
1/3
(2x 1) (x 2)
3(x 2)
?K ?K ?M ?M
1/3
3x 1
0
(x 2)
?M ?] ?M
Critical points x =
1
3
and x = 2
6. Let f(x) be a positive function such that the area
bounded by y = f(x), y = 0 from x = 0 to x = a > 0
is e
–a
+ 4a
2
+ a – 1. Then the differential equation,
whose general solution is y = c
1
f(x) + c
2
, where c
1
and c
2
are arbitrary constants, is :
(1)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?K ?]
(2)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?M ?]
(3)
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
(4)
2
x
2
d y dy
(8e 1) 0
dx dx
?M ?M ?]
Ans. (3)
Sol.
a
a 2
0
f(x)dx e 4a a 1
?M ?] ?K ?K ?M ??
f(a) = –e
–a
+ 8a + 1
f(x) = –e
–x
+ 8x + 1
Now y = C
1
f(x) + C
2
1
dy
C f '(x)
dx
?] = C
1
(e
–x
+ 8) …..(1)
2
2
d y
dx
= –C
1
e
–x
?? –e
x
2
2
d y
dx
Put in equation (1)
2
x x
2
dy d y
e (e 8)
dx dx
?M ?] ?M ?K
2
x
2
d y dy
(8e 1) 0
dx dx
?K ?K ?]
7. Let f(x) = 4cos
3
x + 3 3 cos
2
x – 10. The number
of points of local maxima of f in interval (0, 2 ?? ) is:
(1) 1 (2) 2
(3) 3 (4) 4
Ans. (2)
Sol. f(x) = 4cos
3
(x) + 3 3 cos
2
(x) – 10 ; x ?? (0, 2 ?? )
???@ f'(x) = 12cos
2
x[–sin(x)] + 3 3 (2cos(x))[–sin(x)]
???@ f'(x) = –6sin(x) cos(x)[2cos(x) + 3 ]
–
+
–
+
–
+
–
2 ?? 0
local maxima at x =
5 7
,
6 6
????
8. Let A =
2 a 0
1 3 1
0 5 b
????
????
????
????
. If A
3
= 4A
2
– A – 21I, where
I is the identity matrix of order 3 × 3, then 2a + 3b
is equal to :
(1) –10 (2) –13
(3) –9 (4) –12
Ans. (2)
Sol. A
3
– 4A
2
+ A + 21 I = 0
tr(A) = 4 = 5 + 6 ???@ b = –1
|A| = –21
–16 + a = –21 ?? a = –5
2a + 3b = –13
9. If the shortest distance between the lines
1
ˆˆ ˆ
L : r (2 )i (1 3 )j (3 4 )k, ?] ?K ?? ?K ?M ?? ?K ?K ?? ?? ??
2
ˆˆ ˆ
L : r 2(1 )i 3(1 )j (5 )k, ?] ?K ?? ?K ?K ?? ?K ?K ?? ?? ??
is
m
n
, where gcd (m, n) = 1, then the value of
m + n equals.
(1) 384 (2) 387
(3) 377 (4) 390
Ans. (2)
Sol.
C
D
Shortes distance (CD) =
AB p q
| p q |
????
??
=
ˆ ˆ ˆ ˆ ˆˆ
(0i 2j 2k).( 15i 7j 9k)
355
?K ?K ?M ?K ?K
=
0 14 18
355
?K?K
=
32
355
?| m + n = 32 + 355 = 387
10. Let the sum of two positive integers be 24. If the
probability, that their product is not less than
3
4
times their greatest positive product, is
m
n
,
where gcd(m, n) = 1, then n – m equals :
(1) 9 (2) 11
(3) 8 (4) 10
Ans. (4)
Sol. x + y = 24, x, y ?? ?@ N
AM > GM ???@ xy ?? 144
xy ?? 108
Favorable pairs of (x, y) are
(13, 11), (12, 12), (14, 10), (15, 9), (16, 8),
(17, 7), (18, 6), (6, 18), (7, 17), (8, 16), (9, 15),
(10, 14), (11, 13)
i.e. 13 cases
Total choices for x + y = 24 is 23
Probability =
13 m
23 n
?]
n – m = 10
11. If sinx = –
3
5
, where ?? < x <
3
2
?? ,
then 80(tan
2
x – cosx) is equal to :
(1) 109 (2) 108
(3) 18 (4) 19
Ans. (1)
Sol. sinx =
3
5
?M , ?? < x <
3
2
??
tanx =
3
4
cosx =
4
5
?M
80(tan
2
x – cosx)
=
9 4
80
16 5
????
?K ????
????
= 45 + 64 = 109
12. Let I(x) =
2 2
6
dx
sin x(1 cot x) ?M ?? . If I(0) = 3, then
I
12
?? ????
????
????
is equal to :
(1) 3 (2) 3 3
(3) 6 3 (4) 2 3
Ans. (2)
Sol. I(x) =
2
2 2 2
6dx 6cosec xdx
sin x(1 cot x) (1 cot x)
?] ?M?M
????
Put 1 – cotx = t
cosec
2
x dx = dt
I =
2
6dt 6
c
t t
?M ?]?K
??
I(x) =
6
c
1 cot x
?M ?M , c = 3
I(x) =
6
3
1 cot x
?M ?M ,
6
I 3
12
1 (2 3)
?? ????
?]?M
????
?M?K ????
6 6( 3 1)
I 3 3 3 3 2
12 2
3 1
???M ????
?] ?K ?] ?K ?] ????
?K ????
13. The equations of two sides AB and AC of a
triangle ABC are 4x + y = 14 and 3x – 2y = 5,
respectively. The point
4
2,
3
????
?M ????
????
divides the third
side BC internally in the ratio 2 : 1. The equation
of the side BC is :
(1) x – 6y – 10 = 0 (2) x – 3y – 6 = 0
(3) x + 3y + 2 = 0 (4) x + 6y + 6 = 0
Ans. (3)
Sol.
3x –2y = 5
4x + y = 14
A
B (x
1
, 14 – 4x
1
) C
2 : 1
•
2 1
2x x
2
3
?K ?] ,
?H ?I 2
1
3x 5
2 14 4x
2
3
?M ????
?K?M
????
????
=
4
3
?M
2x
2
+ x
1
= 6, 3x
2
– 4x
1
= – 13
x
2
= 1, x
1
= 4
So, C(1, – 1) , B(4, –2)
m =
1
3
?M
Equation of BC : y + 1 =
1
3
?M (x – 1)
3y + 3 = – x + 1
x + 3y + 2 = 0
14. Let [t] be the greatest integer less than or equal to
t. Let A be the set of al prime factors of 2310 and
f : A ???@ ?? be the function f(x) =
3
2
2
x
log x
5
???? ???? ????
?K ???? ????
????
????
????
???? ???? ????
.
The number of one-to-one functions from A to the
range of f is :
(1) 20 (2) 120
(3) 25 (4) 24
Ans. (2)
Sol. N = 2310 = 231 × 10
= 3 × 11 × 7 × 2 × 5
A = {2, 3, 5, 7, 11}
f(x) =
3
2
2
x
log x
5
???? ???? ????
?K ???? ????
????
???? ???? ????
f(2) = [log
2
(5)] = 2
f(3) = [log
2
(14)] = 3
f(5) = [log
2
(25 + 25)] = 5
f(7) = [log
2
(117)] = 6
f (11) = [log
2
387] = 8
Range of f : B = {2, 3, 5, 6, 8}
No. of one-one functions = 5! = 120
15. Let z be a complex number such that |z + 2| = 1
and lm
z 1 1
z 2 5
?K ????
?] ????
?K ????
. Then the value of
?H ?I Re z 2 ?K
is :
(1)
6
5
(2)
1 6
5
?K
(3)
24
5
(4)
2 6
5
Ans. (4)
Sol. |z + 2| = 1, Im
z 1 1
z 2 5
?K ????
?] ????
?K ????
Let z + 2 = cos ?? + isin ??
1
cos isin
z 2
?] ?? ?M ?? ?K
?@ ??
z 1 1
1
z 2 z 2
?K ?]?M
?K?K
= 1 – (cos ?? – isin ?? )
= (1 – cos ?? ) + isin ??
Im
z 1
z 2
?K ????
????
?K ????
= sin ?? , sin ?? =
1
5
cos ?? = ±
1
1
25
?M = ±
2 6
5
2 6
Re(z 2)
5
?K?]
16. If the set R = {(a, b) ; a + 5b = 42, a, b ?? }
has m elements and
?H ?I m
n!
n 1
1 i
?] ?K ?? = x + iy, where
I = 1 ?M , then the value of m + x + y is :
(1) 8 (2) 12
(3) 4 (4) 5
Ans. (2)
Sol. a + 5b = 42, a, b ???@ N
a = 42 – 5b, b = 1, a = 37
b = 2, a = 32
b = 3, a = 27
b = 8, a = 2
R has "8" elements ???@ m = 8
8
n!
n 1
(1 i ) x iy
?] ?M ?] ?K ??
for n ?? 4, i
n!
= 1
?? (1 – i) + (1 – i
2!
) + (1 – i
3!
)
= 1 – I + 2 + 1 + 1
= 5 – I = x + iy
m + x + y = 8 + 5 – 1 = 12
Read More