SOLUTION: How do I prove that cos(pi/2 - x) = sinx by using the formula cos(x+y)

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Question 1003042: How do I prove that cos(pi/2 - x) = sinx by using the formula cos(x+y)
Answer by jkc52(5) About Me  (Show Source):
You can put this solution on YOUR website!
we have the expression
cos(x-y)=cosxcosy+sinxsiny
thus letting x=pi/2 and y=x
we have cos(pi/2 - x)=(0)*(cosy)+(1)*(sinx)
=sinx