m²x²+1=(3-2m)x
m²x²-(3-2m)x+1=0
该方程有两个不等实根,则判别式大于0
Δ=[-(3-2m)]²-4m²=-12m+9>0,得m<3/4且m≠0
设该方程的两实根为x1、x2,由韦达定理有x1+x2=(3-2m)/m²、x1x2=1/m²
S=1/x1+1/x2=(x1+x2)/x1x2=[(3-2m)/m²]/(1/m²)=3-2m>3-2•(3/4)=3/2
当m≠0时,S≠3
S的取值范围是S>3/2且S≠3
m²x²+1=(3-2m)x
m²x²-(3-2m)x+1=0
该方程有两个不等实根,则判别式大于0
Δ=[-(3-2m)]²-4m²=-12m+9>0,得m<3/4且m≠0
设该方程的两实根为x1、x2,由韦达定理有x1+x2=(3-2m)/m²、x1x2=1/m²
S=1/x1+1/x2=(x1+x2)/x1x2=[(3-2m)/m²]/(1/m²)=3-2m>3-2•(3/4)=3/2
当m≠0时,S≠3
S的取值范围是S>3/2且S≠3