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ICSE Mathematics Previous Year Paper with Solutions - 2023 | ICSE Class 12 Science Previous Year Papers PDF Download

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 Page 1


 
Mathematics 
 
ISC Boards 2023 
 
1. In subparts (i) to (x) choose the correct options and in subparts (xi) to (xv), answer the questions as instructed. 
 
 
Answer (A)  
Sol.   
Let ?? = { 1, 2, 3} 
      ?? = { ( 1, 1) , ( 2, 2) , ( 1, 2) , ( 3,3) , ( 2, 3) }. 
For all ?? ? ?? , we have ( ?? , ?? )? ?? 
i.e., 1,2,3 ? ?? , we have ( 1, 1) , ( 2, 2) , ( 3, 3)? ?? 
So, ?? is reflexive. 
Since ( 1, 2)? ?? but ( 2, 1)? ?? 
Hence, ?? is not symmetric. 
Similarly, ( 1, 2) , ( 2,3)? ?? but ( 1, 3)? ?? 
Here, ?? is not transitive. 
 
ii. If ?? is a square matrix of order 3, then |2?? | is equal to: 
A. 2|?? | 
B. 4|?? | 
C. 8|?? | 
D. 6|?? | 
 
Answer (C)  
Sol.   
We know that, 
|???? | = ?? ?? |?? |, where ?? is order of matrix. 
? |2?? | = 2
3
|?? |  
             = 8|?? | 
 
iii. If the following function is continuous at ?? = 2 then the value of k will be:  
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
A. 2 
B. 3 
C. 5 
D. -1 
 
Answer (C)  
i. A relation ?? on {1, 2, 3} is given by ?? = {(1, 1), (2, 2), (1, 2), (3,3), (2, 3)}. Then the relation ?? is: 
A. Reflexive 
B. Symmetric 
C. Transitive 
D. Symmetric and transitive. 
Page 2


 
Mathematics 
 
ISC Boards 2023 
 
1. In subparts (i) to (x) choose the correct options and in subparts (xi) to (xv), answer the questions as instructed. 
 
 
Answer (A)  
Sol.   
Let ?? = { 1, 2, 3} 
      ?? = { ( 1, 1) , ( 2, 2) , ( 1, 2) , ( 3,3) , ( 2, 3) }. 
For all ?? ? ?? , we have ( ?? , ?? )? ?? 
i.e., 1,2,3 ? ?? , we have ( 1, 1) , ( 2, 2) , ( 3, 3)? ?? 
So, ?? is reflexive. 
Since ( 1, 2)? ?? but ( 2, 1)? ?? 
Hence, ?? is not symmetric. 
Similarly, ( 1, 2) , ( 2,3)? ?? but ( 1, 3)? ?? 
Here, ?? is not transitive. 
 
ii. If ?? is a square matrix of order 3, then |2?? | is equal to: 
A. 2|?? | 
B. 4|?? | 
C. 8|?? | 
D. 6|?? | 
 
Answer (C)  
Sol.   
We know that, 
|???? | = ?? ?? |?? |, where ?? is order of matrix. 
? |2?? | = 2
3
|?? |  
             = 8|?? | 
 
iii. If the following function is continuous at ?? = 2 then the value of k will be:  
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
A. 2 
B. 3 
C. 5 
D. -1 
 
Answer (C)  
i. A relation ?? on {1, 2, 3} is given by ?? = {(1, 1), (2, 2), (1, 2), (3,3), (2, 3)}. Then the relation ?? is: 
A. Reflexive 
B. Symmetric 
C. Transitive 
D. Symmetric and transitive. 
 
Sol. 
              
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
?? ( ?? ) is continuous at ?? = 2  
? lim
?? ?2
-
?? ( ?? )= lim
?? ?2
+
?? ( ?? )= ?? ( 2) 
? 2( 2)+ 1 = 3( 2)- 1 = ?? 
? ?? = 5 
 
iv. An edge of a variable cube is increasing at the rate of 10cm/sec. How fast will the volume of the cube 
increase if the edge is 5 cm long? 
A. 75 ????
3
/?????? 
B. 750 ????
3
/?????? 
C. 7500 ????
3
/?????? 
D. 1250 ????
3
/?????? 
 
Answer (B)  
Sol. 
Let side of the cube is ?? 
Volume = ?? 3
 
Given 
????
????
= 10 ???? /?????? 
?? = ?? 3
 
Differentiate w.r.t ?? 
????
????
= 3?? 2
.
????
????
 
      = 3( 5)
2
× 10 
      = 750 ????
3
/?????? 
 
v. Let ?? ( ?? )= ?? 3
 be a function with domain {0, 1, 2, 3}. Then domain of ?? -1
 is: 
A. { 3, 2, 1, 0} 
B. { 0, -1, -2, -3} 
C. { 0, 1, 8, 27} 
D. { 0, -1, -8, -27} 
 
Answer (C)  
Sol.  
?? ( ?? )= ?? 3
 
Domain = { 0, 1, 2, 3} 
? ?? ( ?? )= { ( 0, 0) , ( 1, 1) , ( 2, 8) , ( 3, 27) } 
? ?? -1
( ?? )= { ( 0, 0) , ( 1, 1) , ( 8, 2) , ( 27, 3) } 
? Domain of ?? -1
= { 0, 1, 8, 27} 
 
 
vi. For the curve ?? 2
= 2?? 3
- 7, the slope of the normal at (2, 3) is: 
A. 4 
B. 
1
4
 
C. -4 
D. 
-1
4
 
 
Answer (D) 
 Sol. 
?? 2
= 2?? 3
- 7 
Differentiate w.r.t ?? 
Page 3


 
Mathematics 
 
ISC Boards 2023 
 
1. In subparts (i) to (x) choose the correct options and in subparts (xi) to (xv), answer the questions as instructed. 
 
 
Answer (A)  
Sol.   
Let ?? = { 1, 2, 3} 
      ?? = { ( 1, 1) , ( 2, 2) , ( 1, 2) , ( 3,3) , ( 2, 3) }. 
For all ?? ? ?? , we have ( ?? , ?? )? ?? 
i.e., 1,2,3 ? ?? , we have ( 1, 1) , ( 2, 2) , ( 3, 3)? ?? 
So, ?? is reflexive. 
Since ( 1, 2)? ?? but ( 2, 1)? ?? 
Hence, ?? is not symmetric. 
Similarly, ( 1, 2) , ( 2,3)? ?? but ( 1, 3)? ?? 
Here, ?? is not transitive. 
 
ii. If ?? is a square matrix of order 3, then |2?? | is equal to: 
A. 2|?? | 
B. 4|?? | 
C. 8|?? | 
D. 6|?? | 
 
Answer (C)  
Sol.   
We know that, 
|???? | = ?? ?? |?? |, where ?? is order of matrix. 
? |2?? | = 2
3
|?? |  
             = 8|?? | 
 
iii. If the following function is continuous at ?? = 2 then the value of k will be:  
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
A. 2 
B. 3 
C. 5 
D. -1 
 
Answer (C)  
i. A relation ?? on {1, 2, 3} is given by ?? = {(1, 1), (2, 2), (1, 2), (3,3), (2, 3)}. Then the relation ?? is: 
A. Reflexive 
B. Symmetric 
C. Transitive 
D. Symmetric and transitive. 
 
Sol. 
              
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
?? ( ?? ) is continuous at ?? = 2  
? lim
?? ?2
-
?? ( ?? )= lim
?? ?2
+
?? ( ?? )= ?? ( 2) 
? 2( 2)+ 1 = 3( 2)- 1 = ?? 
? ?? = 5 
 
iv. An edge of a variable cube is increasing at the rate of 10cm/sec. How fast will the volume of the cube 
increase if the edge is 5 cm long? 
A. 75 ????
3
/?????? 
B. 750 ????
3
/?????? 
C. 7500 ????
3
/?????? 
D. 1250 ????
3
/?????? 
 
Answer (B)  
Sol. 
Let side of the cube is ?? 
Volume = ?? 3
 
Given 
????
????
= 10 ???? /?????? 
?? = ?? 3
 
Differentiate w.r.t ?? 
????
????
= 3?? 2
.
????
????
 
      = 3( 5)
2
× 10 
      = 750 ????
3
/?????? 
 
v. Let ?? ( ?? )= ?? 3
 be a function with domain {0, 1, 2, 3}. Then domain of ?? -1
 is: 
A. { 3, 2, 1, 0} 
B. { 0, -1, -2, -3} 
C. { 0, 1, 8, 27} 
D. { 0, -1, -8, -27} 
 
Answer (C)  
Sol.  
?? ( ?? )= ?? 3
 
Domain = { 0, 1, 2, 3} 
? ?? ( ?? )= { ( 0, 0) , ( 1, 1) , ( 2, 8) , ( 3, 27) } 
? ?? -1
( ?? )= { ( 0, 0) , ( 1, 1) , ( 8, 2) , ( 27, 3) } 
? Domain of ?? -1
= { 0, 1, 8, 27} 
 
 
vi. For the curve ?? 2
= 2?? 3
- 7, the slope of the normal at (2, 3) is: 
A. 4 
B. 
1
4
 
C. -4 
D. 
-1
4
 
 
Answer (D) 
 Sol. 
?? 2
= 2?? 3
- 7 
Differentiate w.r.t ?? 
 
2?? ????
????
= 6?? 2
 
?
????
????
=
3?? 2
?? 
At (2, 3), 
????
????
|
( 2.3)
=
3( 2)
2
3
= 4 
? Slope of Normal =
-1
4
  
 
vii. Evaluate: ?
?? ?? 2
+1
???? 
 
A. 2 log( ?? 2
+ 1)+ ?? 
B. 
1
2
log( ?? 2
+ 1)+ ?? 
C. ?? ?? 2
+1
+ ?? 
D. log?? +
?? 2
2
+ ?? 
 
Answer (B)  
Sol. 
?? = ?
?? ?? 2
+ 1
???? 
Put ?? 2
+ 1 = ?? 
? 2?????? = ???? 
? ?? =
1
2
?
????
?? 
=
1
2
ln?? + ?? 
=
1
2
ln( ?? 2
+ 1)+ ?? 
 
viii. The derivative of log?? with respect to 
1
?? is: 
A. 
1
??   
B. 
-1
?? 3
  
C. -
1
?? 
D. -?? 
Answer (D)  
Sol. 
Let 
1
?? = ?? 
? -
1
?? 2
=
????
????
 
?
????
????
= -?? 2
 
Now, ?? = log?? 
????
????
= (
????
????
)(
????
????
) 
     = (
1
?? )( -?? 2
) 
     = -?? 
 
 
ix. The interval in which the function ?? ( ?? )= 5 + 36?? - 3?? 2
 increases will be: 
A. ( -8, 6) 
B. ( 6, 8)  
C. ( -6, 6)  
D. ( 0, -6)  
 
Answer (B) 
Page 4


 
Mathematics 
 
ISC Boards 2023 
 
1. In subparts (i) to (x) choose the correct options and in subparts (xi) to (xv), answer the questions as instructed. 
 
 
Answer (A)  
Sol.   
Let ?? = { 1, 2, 3} 
      ?? = { ( 1, 1) , ( 2, 2) , ( 1, 2) , ( 3,3) , ( 2, 3) }. 
For all ?? ? ?? , we have ( ?? , ?? )? ?? 
i.e., 1,2,3 ? ?? , we have ( 1, 1) , ( 2, 2) , ( 3, 3)? ?? 
So, ?? is reflexive. 
Since ( 1, 2)? ?? but ( 2, 1)? ?? 
Hence, ?? is not symmetric. 
Similarly, ( 1, 2) , ( 2,3)? ?? but ( 1, 3)? ?? 
Here, ?? is not transitive. 
 
ii. If ?? is a square matrix of order 3, then |2?? | is equal to: 
A. 2|?? | 
B. 4|?? | 
C. 8|?? | 
D. 6|?? | 
 
Answer (C)  
Sol.   
We know that, 
|???? | = ?? ?? |?? |, where ?? is order of matrix. 
? |2?? | = 2
3
|?? |  
             = 8|?? | 
 
iii. If the following function is continuous at ?? = 2 then the value of k will be:  
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
A. 2 
B. 3 
C. 5 
D. -1 
 
Answer (C)  
i. A relation ?? on {1, 2, 3} is given by ?? = {(1, 1), (2, 2), (1, 2), (3,3), (2, 3)}. Then the relation ?? is: 
A. Reflexive 
B. Symmetric 
C. Transitive 
D. Symmetric and transitive. 
 
Sol. 
              
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
?? ( ?? ) is continuous at ?? = 2  
? lim
?? ?2
-
?? ( ?? )= lim
?? ?2
+
?? ( ?? )= ?? ( 2) 
? 2( 2)+ 1 = 3( 2)- 1 = ?? 
? ?? = 5 
 
iv. An edge of a variable cube is increasing at the rate of 10cm/sec. How fast will the volume of the cube 
increase if the edge is 5 cm long? 
A. 75 ????
3
/?????? 
B. 750 ????
3
/?????? 
C. 7500 ????
3
/?????? 
D. 1250 ????
3
/?????? 
 
Answer (B)  
Sol. 
Let side of the cube is ?? 
Volume = ?? 3
 
Given 
????
????
= 10 ???? /?????? 
?? = ?? 3
 
Differentiate w.r.t ?? 
????
????
= 3?? 2
.
????
????
 
      = 3( 5)
2
× 10 
      = 750 ????
3
/?????? 
 
v. Let ?? ( ?? )= ?? 3
 be a function with domain {0, 1, 2, 3}. Then domain of ?? -1
 is: 
A. { 3, 2, 1, 0} 
B. { 0, -1, -2, -3} 
C. { 0, 1, 8, 27} 
D. { 0, -1, -8, -27} 
 
Answer (C)  
Sol.  
?? ( ?? )= ?? 3
 
Domain = { 0, 1, 2, 3} 
? ?? ( ?? )= { ( 0, 0) , ( 1, 1) , ( 2, 8) , ( 3, 27) } 
? ?? -1
( ?? )= { ( 0, 0) , ( 1, 1) , ( 8, 2) , ( 27, 3) } 
? Domain of ?? -1
= { 0, 1, 8, 27} 
 
 
vi. For the curve ?? 2
= 2?? 3
- 7, the slope of the normal at (2, 3) is: 
A. 4 
B. 
1
4
 
C. -4 
D. 
-1
4
 
 
Answer (D) 
 Sol. 
?? 2
= 2?? 3
- 7 
Differentiate w.r.t ?? 
 
2?? ????
????
= 6?? 2
 
?
????
????
=
3?? 2
?? 
At (2, 3), 
????
????
|
( 2.3)
=
3( 2)
2
3
= 4 
? Slope of Normal =
-1
4
  
 
vii. Evaluate: ?
?? ?? 2
+1
???? 
 
A. 2 log( ?? 2
+ 1)+ ?? 
B. 
1
2
log( ?? 2
+ 1)+ ?? 
C. ?? ?? 2
+1
+ ?? 
D. log?? +
?? 2
2
+ ?? 
 
Answer (B)  
Sol. 
?? = ?
?? ?? 2
+ 1
???? 
Put ?? 2
+ 1 = ?? 
? 2?????? = ???? 
? ?? =
1
2
?
????
?? 
=
1
2
ln?? + ?? 
=
1
2
ln( ?? 2
+ 1)+ ?? 
 
viii. The derivative of log?? with respect to 
1
?? is: 
A. 
1
??   
B. 
-1
?? 3
  
C. -
1
?? 
D. -?? 
Answer (D)  
Sol. 
Let 
1
?? = ?? 
? -
1
?? 2
=
????
????
 
?
????
????
= -?? 2
 
Now, ?? = log?? 
????
????
= (
????
????
)(
????
????
) 
     = (
1
?? )( -?? 2
) 
     = -?? 
 
 
ix. The interval in which the function ?? ( ?? )= 5 + 36?? - 3?? 2
 increases will be: 
A. ( -8, 6) 
B. ( 6, 8)  
C. ( -6, 6)  
D. ( 0, -6)  
 
Answer (B) 
 
 Sol.  
?? ( ?? )= ?? + ?????? - ?? ?? ?? 
? ?? '
( ?? )= ???? - ???? = -?? ( ?? - ?? ) 
? ?? '
( ?? )> ?? for ?? < ?? 
? function is increasing in ( -8, ?? ) 
 
 
x. Evaluate ? ?? 17
cos
4
?? ????
1
-1
 
A. 8 
B. 1 
C. -1 
D. 0 
 
Answer (D)  
Sol. 
?? = ? ?? 17
cos
4
?? ????
1
-1
 
Since, ?? 17
cos
4
?? is an odd function.  
And we know that ? ?? ( ?? ) ???? = 0
?? -?? if ?? ( ?? ) is an odd function. 
? ?? = 0 
 
 
xi. Solve the differential equation: 
????
????
= cosec??  
 
Sol. 
????
????
= cosec?? ?
????
cosec?? = ???? 
? sin?? ???? = ???? 
Integrating both sides 
? ? sin?? ???? = ? ???? 
? - cos?? = ?? + ?? 
 
xii. For what value of ?? the matrix [
0 ?? -6 0
] is a skew symmetric matrix? 
Sol. 
?? = [
0 ?? -6 0
] 
For skew symmetric matrix, 
?? = -?? ?? 
? [
0 ?? -6 0
] = - [
0 -6]
?? 0
] 
? [
0 ?? -6 0
] = [
0 6]
-?? 0
] 
? ?? = 6 
 
 
xiii. Evaluate ? |2?? + 1|????
1
0
 
Sol. 
?? = ? |2?? + 1|????
1
0
 
?? = ? ( 2?? + 1) ????
1
0
       [? 2?? + 1 > 0 ? ?? ? ( 0, 1) ] 
   = [?? 2
+ ?? ]
0
1
 
   = 2 
 
xiv. Evaluate ?
1+cos ?? sin
2
?? ???? 
Sol. 
Page 5


 
Mathematics 
 
ISC Boards 2023 
 
1. In subparts (i) to (x) choose the correct options and in subparts (xi) to (xv), answer the questions as instructed. 
 
 
Answer (A)  
Sol.   
Let ?? = { 1, 2, 3} 
      ?? = { ( 1, 1) , ( 2, 2) , ( 1, 2) , ( 3,3) , ( 2, 3) }. 
For all ?? ? ?? , we have ( ?? , ?? )? ?? 
i.e., 1,2,3 ? ?? , we have ( 1, 1) , ( 2, 2) , ( 3, 3)? ?? 
So, ?? is reflexive. 
Since ( 1, 2)? ?? but ( 2, 1)? ?? 
Hence, ?? is not symmetric. 
Similarly, ( 1, 2) , ( 2,3)? ?? but ( 1, 3)? ?? 
Here, ?? is not transitive. 
 
ii. If ?? is a square matrix of order 3, then |2?? | is equal to: 
A. 2|?? | 
B. 4|?? | 
C. 8|?? | 
D. 6|?? | 
 
Answer (C)  
Sol.   
We know that, 
|???? | = ?? ?? |?? |, where ?? is order of matrix. 
? |2?? | = 2
3
|?? |  
             = 8|?? | 
 
iii. If the following function is continuous at ?? = 2 then the value of k will be:  
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
A. 2 
B. 3 
C. 5 
D. -1 
 
Answer (C)  
i. A relation ?? on {1, 2, 3} is given by ?? = {(1, 1), (2, 2), (1, 2), (3,3), (2, 3)}. Then the relation ?? is: 
A. Reflexive 
B. Symmetric 
C. Transitive 
D. Symmetric and transitive. 
 
Sol. 
              
?? ( ?? )= {
2?? + 1, ???? ?? < 2
?? , ???? ?? = 2
3?? - 1, ???? ?? > 2
 
?? ( ?? ) is continuous at ?? = 2  
? lim
?? ?2
-
?? ( ?? )= lim
?? ?2
+
?? ( ?? )= ?? ( 2) 
? 2( 2)+ 1 = 3( 2)- 1 = ?? 
? ?? = 5 
 
iv. An edge of a variable cube is increasing at the rate of 10cm/sec. How fast will the volume of the cube 
increase if the edge is 5 cm long? 
A. 75 ????
3
/?????? 
B. 750 ????
3
/?????? 
C. 7500 ????
3
/?????? 
D. 1250 ????
3
/?????? 
 
Answer (B)  
Sol. 
Let side of the cube is ?? 
Volume = ?? 3
 
Given 
????
????
= 10 ???? /?????? 
?? = ?? 3
 
Differentiate w.r.t ?? 
????
????
= 3?? 2
.
????
????
 
      = 3( 5)
2
× 10 
      = 750 ????
3
/?????? 
 
v. Let ?? ( ?? )= ?? 3
 be a function with domain {0, 1, 2, 3}. Then domain of ?? -1
 is: 
A. { 3, 2, 1, 0} 
B. { 0, -1, -2, -3} 
C. { 0, 1, 8, 27} 
D. { 0, -1, -8, -27} 
 
Answer (C)  
Sol.  
?? ( ?? )= ?? 3
 
Domain = { 0, 1, 2, 3} 
? ?? ( ?? )= { ( 0, 0) , ( 1, 1) , ( 2, 8) , ( 3, 27) } 
? ?? -1
( ?? )= { ( 0, 0) , ( 1, 1) , ( 8, 2) , ( 27, 3) } 
? Domain of ?? -1
= { 0, 1, 8, 27} 
 
 
vi. For the curve ?? 2
= 2?? 3
- 7, the slope of the normal at (2, 3) is: 
A. 4 
B. 
1
4
 
C. -4 
D. 
-1
4
 
 
Answer (D) 
 Sol. 
?? 2
= 2?? 3
- 7 
Differentiate w.r.t ?? 
 
2?? ????
????
= 6?? 2
 
?
????
????
=
3?? 2
?? 
At (2, 3), 
????
????
|
( 2.3)
=
3( 2)
2
3
= 4 
? Slope of Normal =
-1
4
  
 
vii. Evaluate: ?
?? ?? 2
+1
???? 
 
A. 2 log( ?? 2
+ 1)+ ?? 
B. 
1
2
log( ?? 2
+ 1)+ ?? 
C. ?? ?? 2
+1
+ ?? 
D. log?? +
?? 2
2
+ ?? 
 
Answer (B)  
Sol. 
?? = ?
?? ?? 2
+ 1
???? 
Put ?? 2
+ 1 = ?? 
? 2?????? = ???? 
? ?? =
1
2
?
????
?? 
=
1
2
ln?? + ?? 
=
1
2
ln( ?? 2
+ 1)+ ?? 
 
viii. The derivative of log?? with respect to 
1
?? is: 
A. 
1
??   
B. 
-1
?? 3
  
C. -
1
?? 
D. -?? 
Answer (D)  
Sol. 
Let 
1
?? = ?? 
? -
1
?? 2
=
????
????
 
?
????
????
= -?? 2
 
Now, ?? = log?? 
????
????
= (
????
????
)(
????
????
) 
     = (
1
?? )( -?? 2
) 
     = -?? 
 
 
ix. The interval in which the function ?? ( ?? )= 5 + 36?? - 3?? 2
 increases will be: 
A. ( -8, 6) 
B. ( 6, 8)  
C. ( -6, 6)  
D. ( 0, -6)  
 
Answer (B) 
 
 Sol.  
?? ( ?? )= ?? + ?????? - ?? ?? ?? 
? ?? '
( ?? )= ???? - ???? = -?? ( ?? - ?? ) 
? ?? '
( ?? )> ?? for ?? < ?? 
? function is increasing in ( -8, ?? ) 
 
 
x. Evaluate ? ?? 17
cos
4
?? ????
1
-1
 
A. 8 
B. 1 
C. -1 
D. 0 
 
Answer (D)  
Sol. 
?? = ? ?? 17
cos
4
?? ????
1
-1
 
Since, ?? 17
cos
4
?? is an odd function.  
And we know that ? ?? ( ?? ) ???? = 0
?? -?? if ?? ( ?? ) is an odd function. 
? ?? = 0 
 
 
xi. Solve the differential equation: 
????
????
= cosec??  
 
Sol. 
????
????
= cosec?? ?
????
cosec?? = ???? 
? sin?? ???? = ???? 
Integrating both sides 
? ? sin?? ???? = ? ???? 
? - cos?? = ?? + ?? 
 
xii. For what value of ?? the matrix [
0 ?? -6 0
] is a skew symmetric matrix? 
Sol. 
?? = [
0 ?? -6 0
] 
For skew symmetric matrix, 
?? = -?? ?? 
? [
0 ?? -6 0
] = - [
0 -6]
?? 0
] 
? [
0 ?? -6 0
] = [
0 6]
-?? 0
] 
? ?? = 6 
 
 
xiii. Evaluate ? |2?? + 1|????
1
0
 
Sol. 
?? = ? |2?? + 1|????
1
0
 
?? = ? ( 2?? + 1) ????
1
0
       [? 2?? + 1 > 0 ? ?? ? ( 0, 1) ] 
   = [?? 2
+ ?? ]
0
1
 
   = 2 
 
xiv. Evaluate ?
1+cos ?? sin
2
?? ???? 
Sol. 
 
?? = ?
1 + cos?? sin
2
?? 
= ? (
1
sin
2
?? +
cos?? sin
2
?? )???? 
= ?( cosec
2
?? + cosec?? · cot?? ) ???? 
= - cot?? - cosec?? + ?? 
 
xv. A bag contains 19 tickets, numbered from 1 to 19. Two tickets are drawn randomly in succession with 
replacement. Find the probability that both the tickets drawn are even numbers.  
 
Sol. 
No. of even numbers from 1 to 19 is 9. 
? Required probability is, 
?? = (
9
19
)× (
9
19
) 
    =
81
361
 
 
2.  
i. If ?? ( ?? )= [4 - ( ?? - 7)
3
]
1
5
 is a real invertible function, then find ?? -1
( ?? ) 
Sol. 
?? ( ?? )= [4 - ( ?? - 7)
3
]
1
5
 
Let ?? = [4 - ( ?? - 7) )
3
]
1
5
 
? ?? 5
= 4 - ( ?? - 7) )
3
 
? ( ?? - 7)
3
= 4 - ?? 5
 
? ?? - 7 = ( 4 - ?? 5
)
1
3
 
? ?? = 7 + ( 4 - ?? 5
)
1
3
 
Now, replace ?? by ?? 
? ?? = 7 + ( 4 - ?? 5
)
1
3
 
? ?? -1
( ?? )= 7 + ( 4 - ?? 5
)
1
3
 
 
OR 
ii. Let ?? = R - { 2} and ?? = R - { 1}. If ?? ; ?? ? ?? is a function defined by ?? ( ?? )=
?? -1
?? -2
 then show that ?? is a one-one and 
an onto function. 
Sol. 
Given, ?? = R - { ?? }, ?? = R - { ?? } 
?? ( ?? )=
?? - ?? ?? - ?? 
For one-one function 
?? ( ?? ?? )= ?? ( ?? ?? ) 
?
?? ?? - ?? ?? ?? - ?? =
?? ?? - ?? ?? ?? - ?? 
? ?? ?? ?? ?? - ?? ?? ?? - ?? ?? + ?? = ?? ?? ?? ?? - ?? ?? - ?? ?? ?? + ?? 
? ?? ?? = ?? ?? 
? ?? ( ?? ) is one – one function. 
For onto function ?? ? ?? 
? ?? =
?? - ?? ?? - ?? 
? ???? - ???? = ?? - ?? 
? ?? ( ?? - ?? )= ???? - ?? 
? ?? =
???? - ?? ?? - ?? 
? ?? ? ?? ? ?? ? ??  
? ?? ( ?? ) is onto function. 
 
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