If sin a sin b -cos a cos b+1=0 then the value of sin(a+b) is​

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If sin a sin b -cos a cos b+1=0 then the value of sin(a+b) is​

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Natalia 4 weeks 2021-08-16T17:09:08+00:00 1 Answer 0 views 0

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    2021-08-16T17:10:19+00:00

    Answer:

    Given sina sinb – cosa cosb + 1= 0. The formula of (sinasinb- cosa cosb )= cos(a+b) . i.e cos(a+b) +1=0. cos(a+b) = 0-1, cos(a+b) = -1. cos 180°= -1. Now cos(a+b) = cos(180) . Now by comparing Lhs and Rhs, we get a+b= 180° . substitute a+b= 180° in sin(a+b) = sin (180°) = sin(90+90)= – cos(90°) = 0. Hence the value of sin(a+b) = 0. Hope this helps you.

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