如图,抛物线\(y=ax^{2}+bx+c(a,b,c\)是常数,\(a\neq 0)\)与\(x\)轴交于\(A\),\(B\)两点,顶点\(P(m,n).\)给出下列结论:
\(①2a+c < 0\);
\(②\)若\((- \dfrac {3}{2},y_{1})\),\((- \dfrac {1}{2},y_{2})\),\(( \dfrac {1}{2},y_{3})\)在抛物线上,则\(y_{1} > y_{2} > y_{3}\);
\(③\)关于\(x\)的方程\(ax^{2}+bx+k=0\)有实数解,则\(k > c-n\);
\(④\)当\(n=- \dfrac {1}{a}\)时,\(\triangle ABP\)为等腰直角三角形.
其中正确结论是 ______ \((\)填写序号\()\).