Published by:
CGP EDU Academic Team
Published on: August 13, 2026
If 0 ≤ x < 2 π , then the number of real values of x, which satisfy the equation
cosx + cos2x + cos3x + cos4x = 0, is
Text Solution
Verified by ExpertsThe correct answer is:
B
Sol. 0 ≤ x < 2 π
cos x + cos2x + cos3x + cos4x = 0
(cosx + cos4x) + (cos 2x + cos3x) = 0
2 cos 
cos 
+ 2 cos 
cos 
= 0
2 cos 
= 0
cos 
= 0 or cos x = 0 or cos 
= 0
x = 
or x = (2n + 1) 
or x = (2n + 1) π
x = 
Number of solution is 7
──────────────────────────────────────────────────────────────────────────────────────────
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