求z关于u和v的偏导数:z=ln(e^x+y),x=u*v,y=u-v
根据链式法则,有:
zu = (∂z/∂u) = (∂z/∂x) * (∂x/∂u) + (∂z/∂y) * (∂y/∂u)
zv = (∂z/∂v) = (∂z/∂x) * (∂x/∂v) + (∂z/∂y) * (∂y/∂v)
首先计算偏导数:
∂z/∂x = 1/(e^x+y) * (e^x+y) = 1
∂z/∂y = 1/(e^x+y) * 1 = 1/(e^x+y)
∂x/∂u = v
∂x/∂v = u
∂y/∂u = 1
∂y/∂v = -1
代入公式得:
zu = (∂z/∂x) * (∂x/∂u) + (∂z/∂y) * (∂y/∂u) = v + 1/(e^x+y)
zv = (∂z/∂x) * (∂x/∂v) + (∂z/∂y) * (∂y/∂v) = u - 1/(e^x+y)
化简可得:
zu = v + 1/(e^(u*v+u-v)+1)
zv = u - 1/(e^(u*v+u-v)+1)
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