Question

高等数学下册题求做题步骤

能写纸上更好 直接说我也能看

Answer 1

u = xy^2 + yz, u'<x> = y^2, u'<y> = 2xy + z, u'<z> = y
方向余弦 (1/√2, 0, 1/√2)
∂u/∂L = (1/√2)y^2 + (1/√2)y
在 P(1, 2, 3), ∂u/∂L = (1/√2)2^2 + (1/√2)2 = 3√2