3/√2-√2
=3√2/(√2*√2)-√2
=3√2/2-√2
=(3√2-2√2)/2
=√2/2我的意思是大根号里面是2分之3减根号2√(3/2-√2)=√[1/4*(6-4√2)]=√[1/4*(2-√2)^2]=(2-√2)/2