椭圆x^2/25+y^2/9=1上有三点A(x1,y1)、B(4,9/5)、C(x2,y2)与右焦点F(4,0)的距离成等差数列,
问题描述:
椭圆x^2/25+y^2/9=1上有三点A(x1,y1)、B(4,9/5)、C(x2,y2)与右焦点F(4,0)的距离成等差数列,
则x1+x2的值为
(A)6 (B)41/4 (C)8 (D)不确定
答
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