Question

（x2+x+3）/(x+1)最小值（x＞0）

Answer 1

（x2+x+3）/(x+1)

=[x(x+1)+3]/(x+1)

=x+3/(x+1)

=x+1+3/(x+1)-1

>=2√[(x+1)×3/(x+1)]-1

=2√3-1

∴最小值是2√3-1