Math, asked by kunii, 1 year ago

if sinx+sin2x=1 then cox+co2x=?

Answers

Answered by kvnmurty

Sinx + sin2x = 1
2 sin 3x/2 cos x/2 = 1
cos x/2 = 1 / (2 sin 3x/2 )

cos x + cos 2x = 2 cos x/2 cos 3x/2 substitute value of cos x/2 from above
= cos 3x/2 / sin 3x/2 = COT 3x/2

rohitduggal21: put x=(pi/2) in the given equation..

rohitduggal21: it satisfies the eqn.. thus put x=pi/2 in cosx + cos2x..

kvnmurty: There are two solutions to the problem. x = 20.353445 deg and 90 deg. At x=90 deg. cosx+cos2x= -1= cot 3Pi/4 . at x=20.353445 deg, cosx+cos2x=1.695 = cot 30.53 deg . So cot 3x/2 satisfies both solutions.

kvnmurty: please give your rating to the answer.

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