1
Question
cos 4 x = cos 2x·
Open in App
Solution
Given that,
cos 4 x = cos 2 x cos 4 x − cos 2 x = 0 ( ∵ cos x − cos y = − 2 sin x + y 2 sin x − y 2 ) − 2 sin 3 x sin x = 0 sin 3 x sin x = 0
So, either sin 3 x = 0 or sin x = 0 .
General solution for sin 3 x = 0 ,
3 x = n π x = n π 3
Where, n ∈ z
General solution for sin x = 0 ,
x = n π
Where, n ∈ z
Thus, the general solutions are,
For sin 3 x = 0 , x = n π 3
For sin x = 0 , x = n π where, n ∈ z
Given that,
So, either
General solution for
Where,
General solution for
Where,
Thus, the general solutions are,
For
For
Suggest Corrections
0
Similar questions
View More
Join BYJU'S Learning Program
Explore more
Join BYJU'S Learning Program
