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#0fbbffa4-fce0-46ae-a08c-fef259fa7abc基础fill_compute椭圆标准方程与性质直线与圆+圆锥曲线

21.已知椭圆C:x2a2+y2b2=1(a>b>0)C:\frac{{x}^{2}}{{a}^{2}}+\frac{{y}^{2}}{{b}^{2}}=1(a>b>0)的左、右焦点分别为F1F_{1}F2F_{2},过点F2F_{2}且倾斜角为6060\circ的直线llCC交于AABB两点.若△AF1F2AF_{1}F_{2}的面积是△BF1F2BF_{1}F_{2}面积的2倍,则CC的离心率为 ___23\frac{2}{3}___.