Find dy/dx in terms of x and y for: xy = tan(xy)
I'm not too good with this so pls dont skip steps pls.
Last edited by mr fantastic; Apr 25th 2009 at 07:10 AM.
Reason: Removed a careless mispelling that could lead to a misunderstanding.
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anyways, i've gotten this far and need help
d(xy)/dx = d(tanxy)/dx
x * dy/dx +y * dx/dx = sec^2(xy) * (d(xy)/dx)
1 = sec^2(xy)
1 = 1/(cos^2(xy))
cos^2(xy) = 1
// chain rule // expand // move terms to opposite sides // factor out y' // divide
btw, x has been left out of the factorizing line.
which when corrected, and factorised again after dividing, renders y' = -y/x
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