Exercise 7.10
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NCERT Solutions class 12 Maths Integrals
Evaluate the integrals in Exercises 1 to 8 using substitutions.
1. 
Ans. Let I = 
=
……….(i)
Putting 


From eq. (i),
I 
= 
= 
= 
= 
= 
2. 
Ans. Let I =
……….(i)
Putting 


To change the limits of integration from
to 
When 
When 
From eq. (i),
I = 
= 
= 
= 
= 
= 
= 
= 
= 
= 
= 
= 
= 
3.
Ans. Let I =
……….(i)
Putting 


Limits of integration, when 

when 

From eq. (i),
I = 
= 
= 
= 
= 
[Applying Product Rule]
= 
= 
= 
= 
= 
= 
= 
4.
Ans. Let I =
……….(i)
Putting 



Limits of integration when
and when 
From eq. (i),
I = 
= 
= 
= 
= 
= 
= 
= 
= 
= 
5. 
Ans. Let I = 
=
……….(i)
Putting 


Limits of integration when
and when 
From eq. (i), I = 
= 
= 
= 
= 
6. 
Ans. 
= 
= 
= 
= 
= 
= 

= 
= 
= 
= 
= 
= 
= 
= 
= 
= 
7. 
Ans. Let I = 
= 
=
……….(i)
Putting 


Limits of integration when
and when 
From eq. (i), I = 
= 

= 
= 
= 
8.
Ans. Let I =
……….(i)
Putting 



Limits of integration when
and when 
From eq. (i),
I = 
= 
= 
= 
= 
= 
= 
= 
= 
NCERT Solutions class 12 Maths Exercise 7.10
Choose the correct answer in Exercises 9 and 10.
9. The value of the integral
is:
(A) 6
(B) 0
(C) 3
(D) 4
Ans. Let I = 
= 
= 
= 
= 
=
……….(i)
Putting 


Limits of integration when
and when 
From eq. (i),
I = 
= 
= 
= 
= 
= 
Therefore, option (A) is correct.
10. If
then
is:
(A) 
(B) 
(C) 
(D)
Ans. 
= 
[Applying Product Rule]
= 
= 
= 
= 


= 
Therefore, option (B) is correct.