已知函數(shù)f(x)=x 的絕對(duì)值/(X-1)-kx 使f(x)存在正數(shù)零點(diǎn)的K的取值范圍為集合A,使f(x)存在負(fù)數(shù)零點(diǎn)的K的取值范圍為集合B.
(1)求A .B
(2)當(dāng)K分別為何值時(shí),f(X)有一個(gè)零點(diǎn)?兩個(gè)零點(diǎn)?三個(gè)零點(diǎn)?
函數(shù)f(x)=x 的絕對(duì)值/(X-1)-kx
x>=0 f(x)=x/(x-1)-kx=[-kx^2+(1+k)x]/(x-1)
x1=0 x2=(k+1)/k>0A={k|k>0或k<-1}
x<=0f(x)=-x/(x-1)-kx=[-kx^2+(k-1)x]/(x-1)
x1=0 x2=(k-1)/k<0 B={k|0
k=0,1,-1時(shí),有一個(gè)零點(diǎn)
0
k>0 或k<-1有兩個(gè)零點(diǎn)