∴x1+x2=4,x1x2=1
∴x2-x1=2
3 |
設(shè)兩個(gè)極值點(diǎn)所對應(yīng)的圖象上兩點(diǎn)的坐標(biāo)為(x1,y1),(x2,y2)
則y1-y2=(x13-6x12+3x1+t)-(x13-6x12+3x1+t)=12
3 |
∴函數(shù)f(x)兩個(gè)極值點(diǎn)所對應(yīng)的圖象上兩點(diǎn)之間的距離為
12+(12
|
111 |
(2)f′(x)=(3x2-12x+3)ex+(x3-6x2+3x+t)ex=(x3-3x2-9x+t+3)ex
∵g(x)有三個(gè)不同的極值點(diǎn)
∴x3-3x2-9x+t+3=0有三個(gè)不等根;
令h(x)=x3-3x2-9x+t+3,則h′(x)=3x2-6x-9=3(x+1)(x-3)
∴h(x)在(-∞,-1),(3,+∞)上遞增,在(-1,3)上遞減
∵h(yuǎn)(x)有三個(gè)零點(diǎn)
∴h(-1)>0,h(3)<0
∴t+8>0,t-24<0
∴-8<t<24.