对数求导法能否用于隐函数的求导?

可以啊
比如
y^x = x^y
xlny = ylnx
d(xlny) = d(ylnx)
lnydx + (x/y)dy = lnxdy + (y/x)dx
[lnx - (x/y)]dy = [lny - (y/x)]dx
dy/dx = [lny - (y/x)]/[lnx - (x/y)]