z=x^(xy) 的偏导数?
两边取对数:
lnz = xy lnx
∂lnz/∂x = ∂z/z∂x = y(lnx+1)
∂z/∂x = z(lnx+1) = x^(xy) (lnx+1)y
∂lnz/∂y = ∂z/z∂y = xlnx
∂z/∂y = zxlnx = x^(xy+1) lnx
z=x^(xy) 的偏导数?
两边取对数:
lnz = xy lnx
∂lnz/∂x = ∂z/z∂x = y(lnx+1)
∂z/∂x = z(lnx+1) = x^(xy) (lnx+1)y
∂lnz/∂y = ∂z/z∂y = xlnx
∂z/∂y = zxlnx = x^(xy+1) lnx