Page 1
JEE Main Previous Year Questions
(2025): Application of Derivatives
Q1: If the set of all values of ?? , for which the equation ?? ?? ?? -???? ?? -?? =?? has three
distinct real roots, is the interval (?? ,?? ), then ?? -?? ?? is equal to ____ .
JEE Main 2025 (Online) 23rd January Morning Shift
Ans: 30
Solution:
5?? 3
-15?? -?? =0
?? (?? )=5?? 3
-15??
?? '
(?? )=15?? 2
-15=15(?? -1)(?? +1)
a?(-10,10)
?? =-10,?? =10
?? -2?? =10+20=30
Q2: Let ?? (?? ,-?? ),?? (?? ,?? ) and ?? (?? ,-?? ) be the vertices of a triangle ABC . Then the
maximum area of the parallelogram ???????? , formed with vertices ?? ,?? and ?? on the
sides ???? ,???? and ???? of the triangle ?????? respectively, is ____
JEE Main 2025 (Online) 2nd April Evening Shift
Page 2
JEE Main Previous Year Questions
(2025): Application of Derivatives
Q1: If the set of all values of ?? , for which the equation ?? ?? ?? -???? ?? -?? =?? has three
distinct real roots, is the interval (?? ,?? ), then ?? -?? ?? is equal to ____ .
JEE Main 2025 (Online) 23rd January Morning Shift
Ans: 30
Solution:
5?? 3
-15?? -?? =0
?? (?? )=5?? 3
-15??
?? '
(?? )=15?? 2
-15=15(?? -1)(?? +1)
a?(-10,10)
?? =-10,?? =10
?? -2?? =10+20=30
Q2: Let ?? (?? ,-?? ),?? (?? ,?? ) and ?? (?? ,-?? ) be the vertices of a triangle ABC . Then the
maximum area of the parallelogram ???????? , formed with vertices ?? ,?? and ?? on the
sides ???? ,???? and ???? of the triangle ?????? respectively, is ____
JEE Main 2025 (Online) 2nd April Evening Shift
Ans: 3
Solution:
The maximum area of such a parallelogram ???????? , with one vertex fixed at ?? and the other
three points lying on the sides of triangle ?????? , is half the area of triangle ?????? .
Using the determinant formula for area of triangle with vertices ?? (?? 1
,?? 1
),?? (?? 2
,?? 2
),?? (?? 3
,?? 3
) :
Area ???????
=
1
2
?? 1
(?? 2
-?? 3
2
)+?? 2
(?? 3
-?? 1
)+?? 3
(?? 1
-?? 2
)|
Substitute the coordinates:
=
1
2
|4(1-(-3))+1((-3)-(-2))+9((-2)-1)|
=
1
2
|4(4)+1(-1)+9(-3)|
=
1
2
|16-1-27|=
1
2
|-12|=
12
2
=6
Maximum area of parallelogram ???????? =
1
2
× area of triangle =
1
2
×6=3
Q3: Let ?? (?? )=?
?? ?? ?? ?
?? ?? -???? +????
?? ?? ???? ,?? ??? . Then the numbers of local maximum and local
minimum points of ?? , respectively, are :
JEE Main 2025 (Online) 22nd January Evening Shift
Options:
A. 3 and 2
B. 2 and 2
C. 2 and 3
D. 1 and 3
Page 3
JEE Main Previous Year Questions
(2025): Application of Derivatives
Q1: If the set of all values of ?? , for which the equation ?? ?? ?? -???? ?? -?? =?? has three
distinct real roots, is the interval (?? ,?? ), then ?? -?? ?? is equal to ____ .
JEE Main 2025 (Online) 23rd January Morning Shift
Ans: 30
Solution:
5?? 3
-15?? -?? =0
?? (?? )=5?? 3
-15??
?? '
(?? )=15?? 2
-15=15(?? -1)(?? +1)
a?(-10,10)
?? =-10,?? =10
?? -2?? =10+20=30
Q2: Let ?? (?? ,-?? ),?? (?? ,?? ) and ?? (?? ,-?? ) be the vertices of a triangle ABC . Then the
maximum area of the parallelogram ???????? , formed with vertices ?? ,?? and ?? on the
sides ???? ,???? and ???? of the triangle ?????? respectively, is ____
JEE Main 2025 (Online) 2nd April Evening Shift
Ans: 3
Solution:
The maximum area of such a parallelogram ???????? , with one vertex fixed at ?? and the other
three points lying on the sides of triangle ?????? , is half the area of triangle ?????? .
Using the determinant formula for area of triangle with vertices ?? (?? 1
,?? 1
),?? (?? 2
,?? 2
),?? (?? 3
,?? 3
) :
Area ???????
=
1
2
?? 1
(?? 2
-?? 3
2
)+?? 2
(?? 3
-?? 1
)+?? 3
(?? 1
-?? 2
)|
Substitute the coordinates:
=
1
2
|4(1-(-3))+1((-3)-(-2))+9((-2)-1)|
=
1
2
|4(4)+1(-1)+9(-3)|
=
1
2
|16-1-27|=
1
2
|-12|=
12
2
=6
Maximum area of parallelogram ???????? =
1
2
× area of triangle =
1
2
×6=3
Q3: Let ?? (?? )=?
?? ?? ?? ?
?? ?? -???? +????
?? ?? ???? ,?? ??? . Then the numbers of local maximum and local
minimum points of ?? , respectively, are :
JEE Main 2025 (Online) 22nd January Evening Shift
Options:
A. 3 and 2
B. 2 and 2
C. 2 and 3
D. 1 and 3
Ans: C
Solution:
We are given
?? (?? )=?
0
?? 2
?
?? 2
-8?? +15
?? ?? ???? ,?? ?R.
To find the local extrema, we first compute the derivative using the Fundamental Theorem of
Calculus and the chain rule.
Step 1. Rewrite the derivative:
Let
?? (?? )=?
0
?? ?
?? 2
-8?? +15
?? ?? ???? ,
so that
?? (?? )=?? (?? 2
).
Then by the chain rule,
?? '
(?? )=?? '
(?? 2
)·2?? .
Since
?? '
(?? )=
?? 2
-8?? +15
?? ?? ,
we substitute ?? =?? 2
to get
?? '
(?? )=
(?? 2
)
2
-8?? 2
+15
?? ?? 2
·2?? =
2?? (?? 4
-8?? 2
+15)
?? ?? 2
.
Step 2. Factor and Identify Critical Points:
Factor the polynomial ?? 4
-8?? 2
+15 by writing it in terms of ?? 2
. Let ?? =?? 2
, then
?? 2
-8?? +15=(?? -3)(?? -5)
so that
?? 4
-8?? 2
+15=(?? 2
-3)(?? 2
-5).
Thus,
?? '
(?? )=
2?? (?? 2
-3)(?? 2
-5)
?? ?? 2
.
Since ?? ?? 2
>0 for all ?? , the zeros of ?? '
(?? ) are determined by
2?? (?? 2
-3)(?? 2
-5)=0.
That gives the critical points:
2?? =0??? =0,
?? 2
-3=0??? =±v3,
?? 2
-5=0??? =±v5.
Step 3. Analyzing the Sign of ?? '
(?? ) :
We need to determine the nature (maximum or minimum) by looking at the sign changes of
?? '
(?? ) on the intervals determined by the critical points ?? =-v5,?? =-v3,?? =0,?? =v3, and
?? =v5. Notice that the factor 2?? (?? 2
-3)(?? 2
-5) will dictate the sign.
Let's define:
h(?? )=?? (?? 2
-3)(?? 2
-5).
Examine the sign of h(?? ) in each interval:
For ?? <-v5 :
?? is negative.
?? 2
>5 so ?? 2
-3>0 and ?? 2
-5>0.
Page 4
JEE Main Previous Year Questions
(2025): Application of Derivatives
Q1: If the set of all values of ?? , for which the equation ?? ?? ?? -???? ?? -?? =?? has three
distinct real roots, is the interval (?? ,?? ), then ?? -?? ?? is equal to ____ .
JEE Main 2025 (Online) 23rd January Morning Shift
Ans: 30
Solution:
5?? 3
-15?? -?? =0
?? (?? )=5?? 3
-15??
?? '
(?? )=15?? 2
-15=15(?? -1)(?? +1)
a?(-10,10)
?? =-10,?? =10
?? -2?? =10+20=30
Q2: Let ?? (?? ,-?? ),?? (?? ,?? ) and ?? (?? ,-?? ) be the vertices of a triangle ABC . Then the
maximum area of the parallelogram ???????? , formed with vertices ?? ,?? and ?? on the
sides ???? ,???? and ???? of the triangle ?????? respectively, is ____
JEE Main 2025 (Online) 2nd April Evening Shift
Ans: 3
Solution:
The maximum area of such a parallelogram ???????? , with one vertex fixed at ?? and the other
three points lying on the sides of triangle ?????? , is half the area of triangle ?????? .
Using the determinant formula for area of triangle with vertices ?? (?? 1
,?? 1
),?? (?? 2
,?? 2
),?? (?? 3
,?? 3
) :
Area ???????
=
1
2
?? 1
(?? 2
-?? 3
2
)+?? 2
(?? 3
-?? 1
)+?? 3
(?? 1
-?? 2
)|
Substitute the coordinates:
=
1
2
|4(1-(-3))+1((-3)-(-2))+9((-2)-1)|
=
1
2
|4(4)+1(-1)+9(-3)|
=
1
2
|16-1-27|=
1
2
|-12|=
12
2
=6
Maximum area of parallelogram ???????? =
1
2
× area of triangle =
1
2
×6=3
Q3: Let ?? (?? )=?
?? ?? ?? ?
?? ?? -???? +????
?? ?? ???? ,?? ??? . Then the numbers of local maximum and local
minimum points of ?? , respectively, are :
JEE Main 2025 (Online) 22nd January Evening Shift
Options:
A. 3 and 2
B. 2 and 2
C. 2 and 3
D. 1 and 3
Ans: C
Solution:
We are given
?? (?? )=?
0
?? 2
?
?? 2
-8?? +15
?? ?? ???? ,?? ?R.
To find the local extrema, we first compute the derivative using the Fundamental Theorem of
Calculus and the chain rule.
Step 1. Rewrite the derivative:
Let
?? (?? )=?
0
?? ?
?? 2
-8?? +15
?? ?? ???? ,
so that
?? (?? )=?? (?? 2
).
Then by the chain rule,
?? '
(?? )=?? '
(?? 2
)·2?? .
Since
?? '
(?? )=
?? 2
-8?? +15
?? ?? ,
we substitute ?? =?? 2
to get
?? '
(?? )=
(?? 2
)
2
-8?? 2
+15
?? ?? 2
·2?? =
2?? (?? 4
-8?? 2
+15)
?? ?? 2
.
Step 2. Factor and Identify Critical Points:
Factor the polynomial ?? 4
-8?? 2
+15 by writing it in terms of ?? 2
. Let ?? =?? 2
, then
?? 2
-8?? +15=(?? -3)(?? -5)
so that
?? 4
-8?? 2
+15=(?? 2
-3)(?? 2
-5).
Thus,
?? '
(?? )=
2?? (?? 2
-3)(?? 2
-5)
?? ?? 2
.
Since ?? ?? 2
>0 for all ?? , the zeros of ?? '
(?? ) are determined by
2?? (?? 2
-3)(?? 2
-5)=0.
That gives the critical points:
2?? =0??? =0,
?? 2
-3=0??? =±v3,
?? 2
-5=0??? =±v5.
Step 3. Analyzing the Sign of ?? '
(?? ) :
We need to determine the nature (maximum or minimum) by looking at the sign changes of
?? '
(?? ) on the intervals determined by the critical points ?? =-v5,?? =-v3,?? =0,?? =v3, and
?? =v5. Notice that the factor 2?? (?? 2
-3)(?? 2
-5) will dictate the sign.
Let's define:
h(?? )=?? (?? 2
-3)(?? 2
-5).
Examine the sign of h(?? ) in each interval:
For ?? <-v5 :
?? is negative.
?? 2
>5 so ?? 2
-3>0 and ?? 2
-5>0.
Product: negative × positive × positive = negative .
Thus, ?? '
(?? )<0.
For -v5<?? <-v3 :
?? is negative.
?? 2
is between 3 and 5 so ?? 2
-3>0 while ?? 2
-5<0.
Product: negative × positive × negative = positive .
Thus, ?? '
(?? )>0.
For -v3<?? <0 :
?? is negative.
?? 2
<3 so both ?? 2
-3<0 and ?? 2
-5<0.
Product: negative × negative × negative = negative.
Thus, ?? '
(?? )<0.
For 0<?? <v3 :
?? is positive.
?? 2
<3 so both ?? 2
-3<0 and ?? 2
-5<0.
Product: positive × negative × negative = positive .
Thus, ?? '
(?? )>0.
For v3<?? <v5 :
?? is positive.
?? 2
is between 3 and 5 so ?? 2
-3>0 while ?? 2
-5<0.
Product: positive × positive × negative = negative .
Thus, ?? '
(?? )<0.
For ?? >v5 :
?? is positive.
?? 2
>5 so both ?? 2
-3>0 and ?? 2
-5>0.
Product: positive × positive × positive = positive .
Thus, ?? '
(?? )>0.
Step 4. Classify the Critical Points:
At ?? =-v5:?? '
(?? ) changes from negative to positive ? local minimum.
At ?? =-v3:?? '
(?? ) changes from positive to negative ? local maximum.
At ?? =0 : ?? '
(?? ) changes from negative to positive ? local minimum.
At ?? =v3:?? '
(?? ) changes from positive to negative ? local maximum.
At ?? =v5:?? '
(?? ) changes from negative to positive ? local minimum.
Step 5. Conclusion:
There are local maximum points at ?? =-v3 and ?? =v3 (2 points in total), and local minimum
points at ?? =-v5,?? =0, and ?? =v5 ( 3 points in total).
Thus, the numbers of local maximum and local minimum points of ?? are 2 and 3 , respectively.
The correct option is Option C.
Q4: A spherical chocolate ball has a layer of ice-cream of uniform thickness around it.
When the thickness of the ice-cream layer is 1 cm , the ice-cream melts at the rate of
???? ????
?? /?????? and the thickness of the ice-cream layer decreases at the rate of
Page 5
JEE Main Previous Year Questions
(2025): Application of Derivatives
Q1: If the set of all values of ?? , for which the equation ?? ?? ?? -???? ?? -?? =?? has three
distinct real roots, is the interval (?? ,?? ), then ?? -?? ?? is equal to ____ .
JEE Main 2025 (Online) 23rd January Morning Shift
Ans: 30
Solution:
5?? 3
-15?? -?? =0
?? (?? )=5?? 3
-15??
?? '
(?? )=15?? 2
-15=15(?? -1)(?? +1)
a?(-10,10)
?? =-10,?? =10
?? -2?? =10+20=30
Q2: Let ?? (?? ,-?? ),?? (?? ,?? ) and ?? (?? ,-?? ) be the vertices of a triangle ABC . Then the
maximum area of the parallelogram ???????? , formed with vertices ?? ,?? and ?? on the
sides ???? ,???? and ???? of the triangle ?????? respectively, is ____
JEE Main 2025 (Online) 2nd April Evening Shift
Ans: 3
Solution:
The maximum area of such a parallelogram ???????? , with one vertex fixed at ?? and the other
three points lying on the sides of triangle ?????? , is half the area of triangle ?????? .
Using the determinant formula for area of triangle with vertices ?? (?? 1
,?? 1
),?? (?? 2
,?? 2
),?? (?? 3
,?? 3
) :
Area ???????
=
1
2
?? 1
(?? 2
-?? 3
2
)+?? 2
(?? 3
-?? 1
)+?? 3
(?? 1
-?? 2
)|
Substitute the coordinates:
=
1
2
|4(1-(-3))+1((-3)-(-2))+9((-2)-1)|
=
1
2
|4(4)+1(-1)+9(-3)|
=
1
2
|16-1-27|=
1
2
|-12|=
12
2
=6
Maximum area of parallelogram ???????? =
1
2
× area of triangle =
1
2
×6=3
Q3: Let ?? (?? )=?
?? ?? ?? ?
?? ?? -???? +????
?? ?? ???? ,?? ??? . Then the numbers of local maximum and local
minimum points of ?? , respectively, are :
JEE Main 2025 (Online) 22nd January Evening Shift
Options:
A. 3 and 2
B. 2 and 2
C. 2 and 3
D. 1 and 3
Ans: C
Solution:
We are given
?? (?? )=?
0
?? 2
?
?? 2
-8?? +15
?? ?? ???? ,?? ?R.
To find the local extrema, we first compute the derivative using the Fundamental Theorem of
Calculus and the chain rule.
Step 1. Rewrite the derivative:
Let
?? (?? )=?
0
?? ?
?? 2
-8?? +15
?? ?? ???? ,
so that
?? (?? )=?? (?? 2
).
Then by the chain rule,
?? '
(?? )=?? '
(?? 2
)·2?? .
Since
?? '
(?? )=
?? 2
-8?? +15
?? ?? ,
we substitute ?? =?? 2
to get
?? '
(?? )=
(?? 2
)
2
-8?? 2
+15
?? ?? 2
·2?? =
2?? (?? 4
-8?? 2
+15)
?? ?? 2
.
Step 2. Factor and Identify Critical Points:
Factor the polynomial ?? 4
-8?? 2
+15 by writing it in terms of ?? 2
. Let ?? =?? 2
, then
?? 2
-8?? +15=(?? -3)(?? -5)
so that
?? 4
-8?? 2
+15=(?? 2
-3)(?? 2
-5).
Thus,
?? '
(?? )=
2?? (?? 2
-3)(?? 2
-5)
?? ?? 2
.
Since ?? ?? 2
>0 for all ?? , the zeros of ?? '
(?? ) are determined by
2?? (?? 2
-3)(?? 2
-5)=0.
That gives the critical points:
2?? =0??? =0,
?? 2
-3=0??? =±v3,
?? 2
-5=0??? =±v5.
Step 3. Analyzing the Sign of ?? '
(?? ) :
We need to determine the nature (maximum or minimum) by looking at the sign changes of
?? '
(?? ) on the intervals determined by the critical points ?? =-v5,?? =-v3,?? =0,?? =v3, and
?? =v5. Notice that the factor 2?? (?? 2
-3)(?? 2
-5) will dictate the sign.
Let's define:
h(?? )=?? (?? 2
-3)(?? 2
-5).
Examine the sign of h(?? ) in each interval:
For ?? <-v5 :
?? is negative.
?? 2
>5 so ?? 2
-3>0 and ?? 2
-5>0.
Product: negative × positive × positive = negative .
Thus, ?? '
(?? )<0.
For -v5<?? <-v3 :
?? is negative.
?? 2
is between 3 and 5 so ?? 2
-3>0 while ?? 2
-5<0.
Product: negative × positive × negative = positive .
Thus, ?? '
(?? )>0.
For -v3<?? <0 :
?? is negative.
?? 2
<3 so both ?? 2
-3<0 and ?? 2
-5<0.
Product: negative × negative × negative = negative.
Thus, ?? '
(?? )<0.
For 0<?? <v3 :
?? is positive.
?? 2
<3 so both ?? 2
-3<0 and ?? 2
-5<0.
Product: positive × negative × negative = positive .
Thus, ?? '
(?? )>0.
For v3<?? <v5 :
?? is positive.
?? 2
is between 3 and 5 so ?? 2
-3>0 while ?? 2
-5<0.
Product: positive × positive × negative = negative .
Thus, ?? '
(?? )<0.
For ?? >v5 :
?? is positive.
?? 2
>5 so both ?? 2
-3>0 and ?? 2
-5>0.
Product: positive × positive × positive = positive .
Thus, ?? '
(?? )>0.
Step 4. Classify the Critical Points:
At ?? =-v5:?? '
(?? ) changes from negative to positive ? local minimum.
At ?? =-v3:?? '
(?? ) changes from positive to negative ? local maximum.
At ?? =0 : ?? '
(?? ) changes from negative to positive ? local minimum.
At ?? =v3:?? '
(?? ) changes from positive to negative ? local maximum.
At ?? =v5:?? '
(?? ) changes from negative to positive ? local minimum.
Step 5. Conclusion:
There are local maximum points at ?? =-v3 and ?? =v3 (2 points in total), and local minimum
points at ?? =-v5,?? =0, and ?? =v5 ( 3 points in total).
Thus, the numbers of local maximum and local minimum points of ?? are 2 and 3 , respectively.
The correct option is Option C.
Q4: A spherical chocolate ball has a layer of ice-cream of uniform thickness around it.
When the thickness of the ice-cream layer is 1 cm , the ice-cream melts at the rate of
???? ????
?? /?????? and the thickness of the ice-cream layer decreases at the rate of
?? ?? ?? ???? /?????? . The surface area (in ????
?? ) of the chocolate ball (without the ice-cream
layer) is :
JEE Main 2025 (Online) 23rd January Evening Shift
Options:
A. 128??
B. 196??
C. 225??
D. 256??
Ans: D
Solution:
v=
4
3
?? r
3
dv
dt
=4?? r
2
dr
dt
81=4?? r
2
×
1
4??
r
2
=81
r=9
surface area of chocolate =4?? (?? -1)
2
=256??
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