3.
在平面直角坐标系中,点\(F_{1}\)、\(F_{2}\)分别为双曲线\(C\):\( \dfrac {x^{2}}{a^{2}}- \dfrac {y^{2}}{b^{2}}=1(a > 0,b > 0)\)的左、右焦点,双曲线\(C\)的离心率为\(2\),点\((1, \dfrac {3}{2})\)在双曲线\(C\)上\(.\)不在\(x\)轴上的动点\(P\)与动点\(Q\)关于原点\(O\)对称,且四边形\(PF_{1}QF_{2}\)的周长为\(4 \sqrt {2}\).
\((1)\)求动点\(P\)的轨迹方程;
\((2)\)在动点\(P\)的轨迹上有两个不同的点\(M(x_{1},y_{1})\)、\(N(x_{2},y_{2})\),线段\(MN\)的中点为\(G\),已知点\((x_{1},x_{2})\)在圆\(x^{2}+y^{2}=2\)上,求\(|OG|⋅|MN|\)的最大值,并判断此时\(\triangle OMN\)的形状.