(4x²+8x+7)/(1/2x²+x+1)
=2(4x²+8x+7)/(x²+2x+2)
=2[4(x²+2x+2)-1]/(x²+2x+2)
=8 - [2/(x²+2x+2)]
易知当x=-1时,分式8-2/[(x+1)²+1]有最小值=8- 2/1=6
(4x²+8x+7)/(1/2x²+x+1)
=2(4x²+8x+7)/(x²+2x+2)
=2[4(x²+2x+2)-1]/(x²+2x+2)
=8 - [2/(x²+2x+2)]
易知当x=-1时,分式8-2/[(x+1)²+1]有最小值=8- 2/1=6