For the equation given below, evaluate at the point .
y' at (2,1) = ?
so i tried taking the natural log of everything then differentiating both sides and solving for y'.
ln2 + lne^xy - ln2 + lnx = lny +ln9.78
xy + lnx = lny + ln9.78
(1/y)y' = y + xy' + 1/x + 0
y' = y^2 + xy'y + y/x
y' = y^2+(y/x) / 1-xy
then if you plug in (2,1) i get -1.5 and thats not right =(
any advice?