Question

cos 3x=cos x find general solution​

Answer 1

Step-by-step explanation:

Cos 3x = Cos x

4Cos³x - 3Cosx = Cosx

4Cos³x - 4Cosx = 0

4Cosx(Cos²x - 1) = 0

4Cosx = 0

Cosx = 0

x = 90°

& Cos²x = 1

Cosx = 1

x = 0°