6.
给出下列四个命题:\(①\)“若\(x+y\neq 5\),则\(x\neq 2\)或\(y\neq 3\)”是假命题;\(②\)已知在\(\triangle ABC\)中,“\(A < B\)”是“\(\sin A < \sin B\)”成立的充要条件;\(③\)若函数\(f(x)= \begin{cases} \overset{(3a-1)x+4a}{\log _{a}x}\end{cases} \overset{(x < 1)}{(x\geqslant 1)}\),对任意的\(x_{1}\neq x_{2}\)都有\( \dfrac {f(x_{2})-f(x_{1})}{x_{2}-x_{1}} < 0\),则实数\(a\)的取值范围是\(( \dfrac {1}{7},1)\);\(④\)若实数\(x\),\(y∈[-1,1]\),则满足\(x^{2}+y^{2}\geqslant 1\)的概率为\(1- \dfrac {π}{4}.\)其中正确的命题的序号是 ______ \((\)请把正确命题的序号填在横线上\()\).