∵函数μ=ln(x2+y2+z2)在点M(1,2,-2)处偏导数分别为:
μx|(1,2,-2)=
2x
x2+y2+z2
|(1,2,-2)=
2
9
,
μy|(1,2,-2)=
2y
x2+y2+z2
|(1,2,-2)=
4
9
,
μz|(1,2,-2)=
2z
x2+y2+z2
|(1,2,-2)=-
4
9
,
∴函数μ=ln(x2+y2+z2)在点M(1,2,-2)处的梯度gradμ|M=(
2
9
,
4
9
,-
4
9
)
故答案为:gradμ|M=(
2
9
,
4
9
,-
4
9
).