8.
设\(f(x)\)是定义在\([\)一\(1\),\(1]\)上的奇函数,且对任意的\(a\),\(b∈[\)一\(1\),\(1]\),当\(a+b\neq 0\)时,都有\(\dfrac{f(a)+f(b)}{a+b} > 0\).
\((1)\)若\(a > b\),比较\(f(a)\)与\(f(b)\)的大小;
\((2)\)解不等式\(f(x-\dfrac{1}{2}) < f(x-\dfrac{1}{4})\);
\((3)\)设\(P=\{x|y=f(x\)一\(c)\}\),\(Q=\{x|y=f(x-c^{2})\}\),且\(P\bigcap Q=\varnothing \),求实数\(c\)的取值范围.