5.
定义:对于任意\(n∈{N}^{*} \),满足条件\( \dfrac{{a}_{n}+{a}_{n+2}}{2}\leqslant {a}_{n+1} \)且\({a}_{n}\leqslant M (M\)是与\(n\)无关的常数\()\)的无穷数列\(\{a_{n}\}\)称为\(T\)数列。
\((1)\)若\({a}_{n}=-{n}^{2}+8n (n∈{N}^{*} )\),证明:数列\(\{a_{n}\}\)是\(T\)数列;
\((2)\)设数列\(\{b_{n}\}\)的通项为\({b}_{n}=50n-( \dfrac{3}{2}{)}^{n} \),且数列\(\{b_{n}\}\)是\(T\)数列,求常数\(M\)的取值范围;
\((3)\)设数列\({c}_{n}=| \dfrac{p}{n}-1| (n∈{N}^{*} ,1 < p < 2)\),若数列\(\{c_{n}\}\)是\(T\)数列,求\(p\)的取值范围。