You can put this solution on YOUR website! use identities to find sin2x given cosx3/4 and tan>0
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Do you mean cos(x) = 3/4 ?
If so,
sin(x) = sqrt(1 - cos^2) = sqrt(7/16) = sqrt(7)/4
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sin(2x) = 2*sin(x)*cos(x)
= 2*(3/4)*sqrt(7)/4
= 3sqrt(7)/8
