设直线l方程为y=k(x+2),与x^2/2+y^2=1联立消去y得：(1+2k²)x²+8k²x+8k²-2=0,由韦达定理可知：x1+x2=-8k²/(1+2k²)所以y1+y2=k(x1+2)+k(x2+2)=k(x1+x2+4)=4k/(1+2k²)设点P坐标为(x...