等于:根号26/2
√6.5=√(13/2)=√(26/4)=½√26
根号6.5=根号(13/2)=根号(26/4)=1/2 根号26
根号6.5=√26/4 =√26/2
=根号下(13/2)=根号下(26/4)=(根号下26)/2