1.根号2-1分之2+根号18-4倍根号2分之1=√2-2/1+√18-4√(1/2)=0.828227124
2.根号2-1分之2+根号18-4倍根号2分之1=√(2/(2-1))+√18-4√(1/2)=2.828427125
3.根号2-1分之2+根告银号18-4倍根号2分之1=2/(√袜清宴2-1)+√18-4√(1/正蚂2)=6.242640687
2/(腊行√慎局空2-1)+1/(√18-4√2)
=2(√2+1)+1/(-√2)
=2√2+2-√2/宽瞎2
=3/2×√2+2
2倍的根号2-2
确定是根号里面是2-2/1不是2-1/2?