4.
已知函数\(φ(x)= \dfrac {a}{x+1}\),\(a\)为正常数.
\((1)\)若\(f(x)=\ln x+φ(x)\),且\(a= \dfrac {9}{2}\),求函数\(f(x)\)的单调增区间;
\((2)\)若\(g(x)=|\ln x|+φ(x)\),且对任意\(x_{1}\),\(x_{2}∈(0,2]\),\(x_{1}\neq x_{2}\),都有\( \dfrac {g(x_{2})-g(x_{1})}{x_{2}-x_{1}} < -1\),求\(a\)的取值范围.