1.
已知在平面直角坐标系\(xoy\)中,点\(M(\sqrt{3},0),N(-\sqrt{3},0)\),动点\(P\)满足直线\(PM\)与\(PN\)的斜率乘积为\(-\dfrac{2}{3}.(1)\)求动点\(P\)的轨迹方程;\((2)\)设动点\(P\)形成的轨迹为\(C\),\({{F}_{1}}(-1,0),{{F}_{2}}(1,0)\),连接\(P{{F}_{1}}\)与曲线\(C\)的另一个交点为\(A\),连接\(P{{F}_{2}}\)与曲线\(C\)的另一交点为\(B\),设\(\overrightarrow{P{{F}_{1}}}={{\lambda }_{1}}\overrightarrow{{{F}_{1}}A},\overrightarrow{P{{F}_{2}}}={{\lambda }_{2}}\overrightarrow{{{F}_{2}}B},\)证明:\({{\lambda }_{1}}+{{\lambda }_{2}}\)为定值.