4.
\((1)\)若\(f\left(x\right)=\begin{cases}f\left(x-4\right),x > 1 \\ {e}^{x}+\int _{1}^{2} \dfrac{1}{t}dt,x\leqslant 1\end{cases} \),则\(f(2016)=\)________
\((2)\)已知\(z\)是复数,\(z+2i\)与\(\dfrac{z}{2-i} \)均为实数,且复数\({\left(z+ai\right)}^{2} \)在复平面上对应的点在第一象限,则实数的取值范围为_________.
\((3)\)若函数\(g(x)=ax+b\)是函数\(f\left(x\right)=\ln x- \dfrac{1}{x} \)的图像的切线,则\(a+b\)的最小值是______\(.\)
\((4)\)已知\(f(x)=\dfrac{1+\ln x}{x-1} \),\(g(x)=\dfrac{k}{x} (k∈N^{*})\),对任意的\(c > 1\),存在实数\(a\),\(b\)满足\(0 < a < b < c\),使得\(f(c)=f(a)=g(b)\),则\(k\)的最大值为_________.