a²-3a+1=0
a-3+(1/a)=0
a+2+(1/a)=5
a-2+(1/a)=1
两式相除得
(a+2+(1/a))/(a-2+(1/a))=5
上下同时乘以a
(a²+2a+1)/(a²-2a+1)=5
(a+1)²/(a-1)²=5
根号[(a+1)/(a-1)]=根号5
根号[(a+1)/(a²-2)]
=根号[(a+1)/(3a-1-2)]
=根号[(a+1)/3(a-1)]
=根号(5/3)
=(根号15)/3
a²-3a+1=0
a-3+(1/a)=0
a+2+(1/a)=5
a-2+(1/a)=1
两式相除得
(a+2+(1/a))/(a-2+(1/a))=5
上下同时乘以a
(a²+2a+1)/(a²-2a+1)=5
(a+1)²/(a-1)²=5
根号[(a+1)/(a-1)]=根号5
根号[(a+1)/(a²-2)]
=根号[(a+1)/(3a-1-2)]
=根号[(a+1)/3(a-1)]
=根号(5/3)
=(根号15)/3