InterviewSolution
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InterviewSolution
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If cos(a+b)=0 show that sin(a-b)=? |
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Answer» Cos(a+b)=0We know that, Cos 90 = 0 So, Cos(a+b) = Cos 90=> a+b = 90=> a = 90 - b Now, Sin(a-b) = Sin(90-b-b) = Sin(90-2b) = Cos 2b [ as Sin(90-x) = Cos x ]Thus, Sin(a-b) = Cos 2b cos (a+b) =0=> cos (a+b) = cos 90=> a+b = 90=> a = 90- bNowsin(a+b)= sin(90-b-b)= sin(90-2b)= cos 2b [as sin (90 - x) = cos x] cos (a+b) =0=> cos (a+b) = cos 90=> a+b = 90=> a = 90- bNowsin(a+b)= sin(90-b-b)= sin(90-2b)= cos 2b [as sin (90 - x) = cos x] |
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