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Question
How does cos(x-(3.14/2))=cos((3.14/2)-x)?
Hi Heather,
Well, as it happens, and this is a property of the cosine function
cos(-A) = cos(A)
But note that
sin(-A) = -sin(A)
and
tan(-A) = -tan(A)
Also, considering the angle-sum formula
cos(A-B) = cosA.cosB + sinA.sinB
and so
cos(B-A) = cosB.cosA + sinB.sinA
which shows that
cos(A-B) = cos(B-A)
Regards
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Ahmed Salami
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I can provide good answers to questions dealing in almost all of mathematics especially from A`Level downwards. I can as well help a good deal in Physics with most emphasis directed towards mechanics.
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An engineering graduate. I have been doing maths and physics all my life.
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