对于任意正数a,b 我们有:√ab<=(a+b)/2因此:a√(1+b2)=√[a^2(1+b^2)]=√2*√[(a^2*[(1+b^2)/2]]<=√2*[a^2+(1+b^2)/2]/2=√2*[a^2+b^2/2+1/2]/2=3√2/4以上
a√(1+b2)=√[a^2(1+b^2)]=√2*√[(a^2*[(1+b^2)/2]]<=√2*[a^2+(1+b^2)/2]=√2*[a^2+b^2/2+1/2]=3√2/2