Trigonometric EquationHard
Question
Find the general solution of x, 1 + cosx + cos2x = 0
Options
A.(2n - 1) 
; n ∈ I
; n ∈ IB.(2n + 1) 
; n ∈ I
; n ∈ IC.(2n + 1) 
; n ∈ I
; n ∈ ID.(2n + 1) 
; n ∈ I
; n ∈ ISolution
1 + cos x + cos 2x = 0
2 cos2x + cos x = 0
⇒ cos x[2 cos x + 1] = 0
cos x = 0 ⇒ x = (2n + 1)
, (2n - 1) 
2 cos2x + cos x = 0
⇒ cos x[2 cos x + 1] = 0
cos x = 0 ⇒ x = (2n + 1)
, (2n - 1) Create a free account to view solution
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