1/a+1/b+1/ab
=1/a+1/b+(a+b)/ab
=2/a+2/b
=2(a+b)/a+2(a+b)/b
=2+2(b/a+a/b)
a>0,b>0
由均值不等式,得
b/a+a/b≥2√[(b/a)(a/b)]=2
1/a+1/b+1/ab≥2+2×2=6
1/a+1/b+1/ab的最小值为6,此时a=
1/a+1/b+1/ab
=1/a+1/b+(a+b)/ab
=2/a+2/b
=2(a+b)/a+2(a+b)/b
=2+2(b/a+a/b)
a>0,b>0
由均值不等式,得
b/a+a/b≥2√[(b/a)(a/b)]=2
1/a+1/b+1/ab≥2+2×2=6
1/a+1/b+1/ab的最小值为6,此时a=