a=√2=2/√2=4/(2√2)=4/(√2+√2),
b=√7-√3=(√7-√3)( √7+√3)/( √7+√3)=4/( √7+√3),
c=√6-√2=(√6-√2)( √6+√2)/( √6+√2)=4/( √6+√2),
因为√2+√24/( √7+√3)
即a>c>b.