SOLUTION: PROVE THAT: sinx.cosx=-1

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Question 1018512: PROVE THAT:
sinx.cosx=-1
Found 2 solutions by Edwin McCravy, Alan3354:
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
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sinx.cosx=-1


That is NEVER true!



Can't prove TRUE what is NEVER true.

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
PROVE THAT:
sinx.cosx=-1
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That is not an identity.
It can be disproven with 1 counter-example:
sin(0)*cos(0) = 0 not -1
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You can try to solve for x:
sinx*cosx=-1
2sin(x)*cos(x) = -2
sin(2x) = -2
No solution.