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 = 
──────────────────────────────────────────────────────────────────────────────────────────
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems
If log p x = α and log q x = β , then the value of log p/q x is
If log x a, a x/2 and log b x are in G.P. Then x is equal to
If log x 256 = 8/5, then x is equal to
If log 2, log(2 x – 1) and log (2 x + 3) are in A.P., then x is equal to
The roots of the equation log 2 (x 2 – 4x + 5) = (x – 2) are
If x = 198 !, then value of the expression equals