(根号2+1)/(根号2-1)
=[(根号2+1)(根号2+1)]/[(根号2-1)(根号2+1)]
=(3+2根号2)/(2-1)
=3+2根号2
根号2=1.414
2根号2=2.828
3+2根号2=5.828
所以a=5
1-b=3+2根号2-a=-2+2根号2
b=3-2根号2
所以
(a+b)/(a-b)=(5+3-2根号2)/(5-3+2根号2)
=(8-2根号2)/(2+2根号2)
=(4-根号2)/(根号2+1)
=[(4-根号2)(根号2-1)]/[(根号2+1)(根号2-1)]
=-6+5根号2