X的Y次方等于Y的X次方,求Y导数.

问题描述:

X的Y次方等于Y的X次方,求Y导数.

X^Y = Y^X
YlnX = XlnY
lnX·dY + Y/X·dX = lnY·dX + X/Y·dY
(lnX - X/Y)dY = (lnY - Y/X)dX
dY/dX = (lnY - Y/X)/(lnX - X/Y)