(a-1)/a÷{a-(2a-1)/a}、a=√3+1 (a-1)/a÷{a-(2a-1)/a}、a=√3+1

(a-1)/a÷{a-(2a-1)/a}、a=√3+1 (a-1)/a÷{a-(2a-1)/a}、a=√3+1

[(a-1)/a]÷[a-(2a-1)/a]
=[(a-1)/a]÷[(a²-2a+1)/a]
=[(a-1)/a]÷[(a-1)²/a]
=[(a-1)/a]×[a/(a-1)²]
=1/(a-1)
したがって、a=√3+1の場合、元の=1/[(√3+-1]=1/√3=√3/3