8.
已知函数\(f(x)=2- \dfrac{1}{x} \),数列\(\{a_{n}\}\)满足\(a_{n}=f(a_{n-1})(n\geqslant 2,nÎN^{*}).\)
\((\)Ⅰ\()\)若\({a}_{1}= \dfrac{3}{5} \),数列\(\{b_{n}\}\)满足\({b}_{n}= \dfrac{1}{{a}_{n}-1} \),求证:数列\(\{b_{n}\}\)是等差数列;
\((\)Ⅱ\()\)若\({a}_{1}= \dfrac{3}{5} \),数列\(\{a_{n}\}\)中是否存在最大项与最小项,若存在,求出最大项与最小项,若不存在,说明理由;
\((\)Ⅲ\()\)若\(1 < a_{1} < 2\),试用数学归纳法证明:\(1 < a_{n+1} < a_{n} < 2\).