13.已知OOO为坐标原点,F1(−1,0)F_{1}(-1,0)F1(−1,0)是椭圆C:x2a2+y2b2=1(a>b>0)C:\frac{x^2}{a^2}+\frac{y^2}{b^2}=1({a>b>0})C:a2x2+b2y2=1(a>b>0)的左焦点,点PPP是椭圆的上顶点,以点PPP为圆心且过F1F_{1}F1的圆恰好与直线x=2x=\sqrt{2}x=2相切.(1)求椭圆CCC的方程;(2)斜率为1的直线lll交椭圆CCC于AAA,BBB两点,求ΔAOB\Delta AOBΔAOB面积的最大值.