设y1=k1x²,y2=k2/x,则y=y1+y2=k1x²+k2/x,
分别把x=1,y=3;x=-1,y=1代入y=k1x²+k2/x得方程组:
3=k1+k2
1=k1-k2
解得:k1=2,k2=1
再把k1=2,k2=1代入y=k1x²+k2/x得:y=2x²+1/x
当x=-0.5时,y=2×(-0.5)²+1/(-0.5)=0.5-2=-1.5
设y1=k1x²,y2=k2/x,则y=y1+y2=k1x²+k2/x,
分别把x=1,y=3;x=-1,y=1代入y=k1x²+k2/x得方程组:
3=k1+k2
1=k1-k2
解得:k1=2,k2=1
再把k1=2,k2=1代入y=k1x²+k2/x得:y=2x²+1/x
当x=-0.5时,y=2×(-0.5)²+1/(-0.5)=0.5-2=-1.5