Question

高数题求解偏导数

Answer 1

你可以用x代替1/x, y代替1/y, 得：
f(x, y) = 1/x^2 - 2(1/x)(1/y) + 3/y^2
再求偏导数。

Answer 2

f(1/x, 1/y) = x^2-2xy +3y^2
let
u= 1/x, v=1/y
f(1/x, 1/y) = x^2-2xy +3y^2
f(u, v)
= (1/u)^2-2(1/u)(1/v) +3(1/v)^2
=1/u^2 -2/(uv) + 3/v^2
ie
f(x,y)=1/x^2 -2/(xy) + 3/x^2