SOLUTION: How do I verify the identity of (1 + sin(y))[1 + sin(-y)] = cos^2(y)

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Question 659678: How do I verify the identity of
(1 + sin(y))[1 + sin(-y)] = cos^2(y)
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
How do I verify the identity of
(1 + sin(y))[1 + sin(-y)] = cos^2(y)
start with left side:
(1 + sin(y))[1 + sin(-y)]
Identity: sin(-y)=-sin(y)
(1 + sin(y))[1 - sin(y)]
difference of 2 squares
=1-sin^2(y)
=cos^2(y)
verified: left side=right side