# trig

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find the values of x between 0 and 2 pi where the tangent line to the graph of y = sinxcosx is horizontal

• trig -

Hmmmm. Wondering if you are taking calculus.

Calculus
y=sinxcosx
y'=0=cos^2x-sin^2x
cos^2x=sin^2x
tan^2 x=1
tanx= +-1
which occurs at increments of 45 degrees

x= +-PI/4, PI+-Pi/4

check that

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