3.
给出下列结论:
动点\(M(x{,}y)\)分别到两定点\(({-}4{,}0){,}(4{,}0)\)连线的斜率之乘积为\({-}\dfrac{9}{16}\),设\(M(x{,}y)\)的轨迹为曲线\(C{,}F_{1}\)、\(F_{2}\)分别为曲线\(C\)的左右焦点,则下列命题中:
\((1)\)曲线\(C\)的焦点坐标为\(F_{1}({-}5{,}0){,}F_{2}(5{,}0)\);
\((2)\)曲线\(C\)上存在一点\(M\),使得\(S{{\triangle }}_{F1MF2}{=}9\);
\((3)P\)为曲线\(C\)上一点,\(P{,}F_{1}{,}F_{2}\)是直角三角形的三个顶点,且\({|}PF_{1}{| > |}PF_{2}{|}{,}\dfrac{{|}PF_{1}{|}}{{|}PF_{2}{|}}\)的值为\(\dfrac{23}{9}\);
\((4)\)设\(A(1{,}1)\),动点\(P\)在曲线\(C\)上,则\({|}PA{|} + {|}PF_{1}{|}\)的最大值为\(8{+}\sqrt{9{-}2\sqrt{7}}\);其中正确命题的序号是______ .