Question

一道反比例函数题,已知y=y1+y2,y1与x^2成正比,y2与x成反比,且x=1时,y=3；x=-1时,y=1.求x=

Answer 1

设y1=mx² y2=n/x,则y=mx²+n/x

x=1 y=3；x=-1 y=1分别代入,得

m+n=3

m-n=1

解得

m=2 n=1

y=2x²+1/x

x=-0.5代入,得

y=2(-0.5)²+1/(-0.5)=0.5-2=-1.5