2013年高考已经落下帷幕,面对着命题专家半个月辛苦的结晶,笔者想就文理20题谈谈自己的看法,供读者参考,不当之处敬请批评指正.1原题展示已知抛物线C的顶点为原点,其焦点F(0,c)(c>0) The college entrance examination in 2013 has come to an end, in the face of the hard work of proposition experts for half a month, I would like to talk about their views on the issue of liberal arts 20, for your reference, please correct me criticism .1 original show known parabolic The vertex of C is the origin, the focal point F (0, c) (c> 0)