Question

please help me out with this answer please.........

cox 3x + cos x - cos 2x = 0​

Answer 1

Hey!!! Here's your answer

We have,

cos3x + cosx - cos2x = 0

Or 2cos(3x+x/2)cos(3x-x/2)-cos2x =0

Or 2cos2xcosx - cos2x =0

Or cos2x(2cosx-1) =0

So,

cos2x=0 or 2cosx-1=0

General formula for cos2x=0

2x=(2n+1)π/2

x=(2n+1)π/4

General formula for 2cosx-1=0

Let cosx=cosy

cosx=1/2=cosy

cosy=cosπ/3

y=π/3

x=2nπ plusminus π/3

Hope it helps you

Please mark my answer as BraiNLiEsT

Answer 2

Step-by-step explanation:

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