Question #fa425

1 Answer
Sidharth
Mar 14, 2016

Please look below

Explanation:

Lets start with RHS;

(1 + cosx)/ 2 = (1 + cos(2 * x/2))/ 2 = (1 + cos^2 (x/2) - sin^2 (x/2))/2

= ( cos^2 (x/2) +sin^2 (x/2) + cos^2 (x/2) - sin^2 (x/2))/2
= ( cos^2 (x/2) +cancel(sin^2 (x/2)) + cos^2 (x/2) cancel(- sin^2 (x/2)))/2

=( cancel(2)cos^2(x/2))/cancel2 = cos^2 (x/2) = LHS

Hence Verified

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