prove that sin50-sin70+sin10=0
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Answered by
144
Hiiiii.....
= 2 cos( 50 + 70 / 2 ) sin (50 - 70 / 2 ) + sin 10
= - 2 cos 60 × sin 10 + sin 10
= - 2 × 1 / 2 × sin 10 + sin 10
= - sin 10 + sin 10
= 0 ......
= 2 cos( 50 + 70 / 2 ) sin (50 - 70 / 2 ) + sin 10
= - 2 cos 60 × sin 10 + sin 10
= - 2 × 1 / 2 × sin 10 + sin 10
= - sin 10 + sin 10
= 0 ......
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my solution is easy .... mark me as best
Answered by
61
W.K.T sin(a-b) = sin a cos b - cos a sinb, sin(a+b) = sin a cos b + cos a sin b
Given, Sin 50 - sin 70 + sin 10 can be written as
= Sin(60 - 10) - sin(60 + 10) - sin 10
= sin 60 cos 10 - cos 60 sin 10 - (sin 60 cos 10 + cos 60 sin 10) + sin 10
= sin 60 cos 10 - cos 60 sin 10 - sin 60 cos 10 - cos 60 sin 10 + sin 10
= -2 cos 60 sin 10 + sin 10
= -2 * 1/2 sin 10 + sin 10
= -sin 10 + sin 10
= 0.
Hope this helps!
Given, Sin 50 - sin 70 + sin 10 can be written as
= Sin(60 - 10) - sin(60 + 10) - sin 10
= sin 60 cos 10 - cos 60 sin 10 - (sin 60 cos 10 + cos 60 sin 10) + sin 10
= sin 60 cos 10 - cos 60 sin 10 - sin 60 cos 10 - cos 60 sin 10 + sin 10
= -2 cos 60 sin 10 + sin 10
= -2 * 1/2 sin 10 + sin 10
= -sin 10 + sin 10
= 0.
Hope this helps!
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