The strange part is that i checked this result before submitting in wolframaplha and it seems that either i'm totaly incompetent today or wolframalpha gives the incorrect results.
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Why should there be a minus sign?
plot2d(3*x^2/(1-x),[x,0,.9]) appears to be an increasing function in that interval, but your derivative is negative at, say, x=3/4.
Ehh.. found my own mistake. Bug closed.
The strange part is that i checked this result before submitting in wolframaplha and it seems that either i'm totaly incompetent today or wolframalpha gives the incorrect results.
It does look like at least one of the alternate forms in wolframalpha is wrong.
Setting status to closed now.