∴f(x)=
(x+5)(x+2) |
x+1 |
x2+7x+10 |
x+1 |
=
(x+1)2+5(x+1)+4 |
x+1 |
=(x+1)+
4 |
x+1 |
=-[(-x-1)+
4 |
?x?1 |
≤-2
(?x?1)?
|
=-4+5=1.
當(dāng)且僅當(dāng)-x-1=
4 |
?x?1 |
所以當(dāng)且僅當(dāng)x=-3時(shí),f(x)=
(x+5)(x+2) |
x+1 |
(x+5)(x+2) |
x+1 |
(x+5)(x+2) |
x+1 |
x2+7x+10 |
x+1 |
(x+1)2+5(x+1)+4 |
x+1 |
4 |
x+1 |
4 |
?x?1 |
(?x?1)?
|
4 |
?x?1 |
(x+5)(x+2) |
x+1 |