内容正文:
拓展与延伸8
隐零点
4
越
D
做
0
啦
业3
苍
越
0
式
越
式
式
楼
越
业
以
啦
式
这丨
业2
(x,-1)2e
金
风
☒
f(x)=xe*-1,g(x)=Inx-mx,mER
f(x)
h(x =f(x-g(x
h(x)
f(x)
R,f(x)=(x+1)e"
x<-1
f'(x<0
x>-1
f'(x>0
f(x刘
(-0,-1
(-1,+o0)
f(x)
f-=-1
h(x)=xe*-Inx+mx-1
x∈(0,+o)h(x)=0
er_Ing+
+m=0
k(x)=e'_Inx+
+m
h(x)k(x)
K(x)=e_1-(Inx+1)_e'+Inx
r(x)=x"e"+Inx
x2
2)+
x>0
r(x)>0
r(x)
(0,+∞)
ke
r(x)=0
x∈(0,
r(x)<0
(x)<0
x∈(x,+o)r(x)>0
K'(x)>0
k(x)
(0,)
(x,+o0)
k(x)
k(x)=e_Int +1
+m
r(x)=0
xe%+Inxo =0
xoe=In
-e
Xo
>0
p(x)=f刘+1(
(x
(0,+0
e
dsi
xo =-Inxo
Inxo =-Xo
k(x刘
k(xo)=eIno+
-+m=m+1
m>-1
k(x)
Xo
m=-1
(刘
m<-1
(x<0
()
+00
x
+00
k(x)
+00
k(刘
m>-1
h(x)
m=-1
h(x)
m<-1
h(x)
f(x)=e*-Inx-a g(x)=e*-In(x+a)
a≥1
x f(x)
f(x刘
X
x2(x<x2)
g(Inx)=g(Inx2)=0
M()-e'--(x>O
到==e-x>0)N1=e+0
f'(x)
(0,+o0)
f6)=6-2<0f1w=-1>0
66
f)=0e=1
x∈(0,x)
f'(x)<0x∈(x,+o)f'(x)>0
f(x)(0,x)
(0,+o0)
f(x)min =f(xo)=e%-Inxo-a=x0+
-ax→+o,fy→+0
f(x)<0
1
x→0,fx)→+0
f(x)
x+-a<0
Xo
士特2
a
f(x)=f(x2)=0 a=e"-Inx=e*-Inx2
g(Inx)=x-In(Inx +e*-Inx)=-=0
g(Inx2)=0
g(Inx)=g(Inx2)=0
f(x)=e*1-Inx
f(x)
m>0
g(x)=f(x)-m(x-1)
x
1<x0<2
f(x)=e-M"(x)=e-1
0=王川动=+>0
.x>0
Ix)f(x)
:f'(1=0
x∈(0,1
f'(x<0,fx)
x∈(1,+o)
(x)>0,f(x)
(x)
(0,10
(1,+o∞)
.g(x)=f(x)-m(x-1)=e*-Inx-mx+m(m>0)
g1=e-1-mx>0,m>0)
g(x)(0,+o
g1)=-m<0
ga=e用a>->0
t∈(1,1+m)(1,+o)
g(t)=0
x∈(0,t)g'(t)<0,gx)
x∈(t,+o)g'(t)>0,gx)
.g(x)min =g(t)=e-Int-mt+m
g(x)=e*-Inx-mx+m=0
飞=1>1g=e-m=0
m
g(t)=e-Int-mt+m=0
(2-小e4-1M+1-}0e>D
d=2-je-l+1->n
0-1-4小e}+1-e+0i0el+树刘
0=1>0a2到=n2<0
h(t)=0t∈(1,2)
1<x<2
f(x)=e*g(x)=In(x+n)
l:y=x+m
y=f(x)y=g(x)
m,n
':y=s0<s<1
y=f(x)
y=g(x)
A(x,y),B(x2,2),C(x3,3)
x<x2<3
X1,X2,X3
S
y=x+m
y=f(x)
(t,f(+))
f(x)=e"
f'(t)=e'=1
t=0f(t)=e°=1
(0,1
m=1
1:y=x+1y=x+1y=g(x)
(p,8(p)
g)=1gp)=1=1
x+n
p+n
p+n=1
(p,0)p=-1
n=2
m=1n=2
e=x2+1=ln(x3+2)=s
x=Ins x2=s-1 x3=e-2
X1,X2,X3
2x2=X1+x3
2s-2=Ins+e-2 Ins+e-2s=0
1
h(s)=lns+e-2s(0<s<1)
h'(s)=-+e-2
p)=1+e-2
S
+e
0'(s
0,1
pr9=4+e<0g0=-1+e>0
3,5)
e=
p'(so)=0
s
s∈0,)p'(s)<0
s∈(s,1)
0'(s)>0p(s)(0,so)
(5,
0=6-e22-(a-高e刘
1e0,2)
So
So
p(s,)>0
h'(s)>0
h(s)(0,1)
h(e3)=-3+e3-2e3<0
h1)=e-2>0
h(x)
(e,1
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