来自程长峰的问题
设函数f(x,y)=2xy/x^2+y^2,则f(1,y/x)=?
设函数f(x,y)=2xy/x^2+y^2,则f(1,y/x)=?
1回答
2020-05-12 04:49
设函数f(x,y)=2xy/x^2+y^2,则f(1,y/x)=?
设函数f(x,y)=2xy/x^2+y^2,则f(1,y/x)=?
f(x,y)=2xy/(x^2+y^2)
f(1,y/x)
=2(1)(y/x)/(1+(y/x)^2)
=(2y/x)(x^2/(x^2+y^2))
=2xy/(x^2+y^2)