Published by:
CGP EDU Academic Team
Published on: August 13, 2026
If sum of all the solutions of the equation 8 cosx. 
= 1 in [0, π ] is k π , then k is equal to :
A
B
C
D
Text Solution
Verified by ExpertsThe correct answer is:
D
8cosx 
8cosx 
6 cosx – 8 cosx (sin 2 x) –4 cosx = 1
6 cosx – 8 cosx (1 – cos 2 x) – 4 cosx –1 = 0
8 cos 3 x – 6 cosx –1 = 0
2 (4cos 3 x –3 cosx) = 1
cos3x = 
3x = 2n π ± 
x = (6n ± 1) 
n = 0, x = 
n = 1, x= 
, 
s = 
k = 
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