Question
Question: \[\int_{}^{}{\sqrt{\mathbf{1 +}\mathbf{\sin}\left( \frac{\mathbf{x}}{\mathbf{4}} \right)}\mathbf{dx ...
∫1+sin(4x)dx=
A
8(sin8x−cos8x)+c
B
(sin8x+cos8x)+C
C
81(sin8x−cos8x)+c
D
8(cos8x−sin8x)+c
Answer
8(sin8x−cos8x)+c
Explanation
Solution
∫1+sin(4x)dx=∫[(sin28x+cos28x)+(2sin8x.cos8x)]dx =∫(sin8x+cos8x)2
=∫(sin8x+cos8x)dx=1/8−cosx/8+1/8sinx/8
=8(sin8x−cos8x)+c