SOLUTION: Please prove or disprove 2cosx=sin2x Thank you for the help

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Question 1151361: Please prove or disprove
2cosx=sin2x
Thank you for the help

Answer by ikleyn(52908) About Me  (Show Source):
You can put this solution on YOUR website!
.
I read this equation as  2cos(x) = sin(2x).



It is NOT POSSIBLE to "prove or disprove".


For some values of the angle "x" it is TRUE; for other values of the angle "x" it is FALSE.



It is TRUE if and only if x = pi%2F2+%2B+k%2Api.        ANSWER


It is FALSE for all other values of "x".      ANSWER



The correct formulation is 

    "solve the equation  2cos(x) = sin(2x)",

but not "prove or disprove".



My answer is in the post.