Math, asked by souvikmalakar26, 6 months ago

2cosa=x+1/x then cos2a=?​

Answers

Answered by adityaranjan605
1

Answer:

Step-by-step explanation:

L.H.S.= cos 2a

=  2 cos ^2 − 1

= 2 [1/2(x+1/x)]^2

= 1/2 (x^2 + 1/x^2 + 2.x.1/x)-1

= 1/2 (x^2 + 1/x^2)+1/2.2-1

=1/2 (x^2 + 1/x^2)

= R.H.S.

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