

Solution :
Question 3. cos 2
x
cos 4
x
cos 6
x
Solution :
Question 4.
sin
3
(2
x
+ 1)
Solution :
Question 5.
sin
3
x
cos
3
x
Solution :
Question 6. sin
x
sin 2
x
sin 3
x
Solution :
Question 7.
sin 4
x
sin 8
x
Solution :
It is known that,
sin A . sin B = 12cosA-B-cosA+B
∴∫sin4x sin8x dx=∫12cos4x-8x-cos4x+8xdx
=12∫cos-4x-cos12xdx
=12∫cos4x-cos12xdx
=12sin4x4-sin12x12+C
Question 8.
Solution :
Question 9.
Solution :
Find the integrals of the following functions in Exercises 10 to 18.
Question 10. sin
4
x
Solution :
Question 11. cos
4
2
x
Solution :
Question 12.
Solution :
Question 13.
Solution :
Question 14.
Solution :
Question 15. tan
3
2x sec2x
Solution :
Question 16. tan
4
x
Solution :
Question 17.
Solution :
Question 18.
Solution :
Integrate the following functions in Exercises 19 to 22.
Question 19.
Solution :
Question 20.
Solution :
Question 21. sin
−1
(cos
x
)
Solution :
Question 22.
Solution :
Choose the correct answer in Exercise 23 and 24.
Question 23.is equal to:
A. tan x + cot x + C
B. tan x + cosec x + C
C. − tan x + cot x + C
D. tan x + sec x + C
Solution :
Therefore, option (A) is correct.
Question 24. is equal to:
A. − cot ( e x x ) + C
B. tan ( xe x ) + C
C. tan ( e x ) + C
D. cot ( e x ) + C
Solution : Let I =
Let
e
x
x
=
t
Therefore, option (B) is correct.
