SOLUTION: verify that cos(pi/2 + x)=-sinx

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Question 80913: verify that cos(pi/2 + x)=-sinx
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
verify that cos(pi/2 + x)=-sinx
The sum formula that applies here is:
highlight%28cos%28x%2By%29=cos%28x%29%2Acos%28y%29-sin%28x%29%2Asin%28y%29%29
Another important thing to remember is cos%28pi%2F2%29=0 and sin%28pi%2F2%29=1
cos%28pi%2F2%2Bx%29=cos%28pi%2F2%29%2Acos%28x%29-sin%28pi%2F2%29%28sin%28x%29%29
cos%28pi%2F2%2Bx%29=0%2Acos%28x%29-1%2Asin%28x%29
cos%28pi%2F2%2Bx%29=0-sin%28x%29
cos%28pi%2F2%2Bx%29=-sin%28x%29
Happy Calculating!!!!