题目

已知椭圆C：的右焦点为F，点A（一2，2)为椭圆C内一点。若椭圆C上存在一点P，使得｜PA｜＋｜PF｜＝8，则m的最大值是___． 答案：【答案】25【解析】设椭圆的左焦点为F'（﹣2，0），由椭圆的定义可得2＝|PF|+|PF'|，即|PF'|＝2﹣|PF|，可得|PA|﹣|PF'|＝8﹣2，运用三点共线取得最值，解不等式可得m的范围，再由点在椭圆内部，可得所求范围．椭圆C：的右焦点F（2，0），左焦点为F'（﹣2，0），由椭圆的定义可得2＝|PF|+|PF'|，即|PF'|＝2﹣|PFHe is the man who for many people has been a role model. Now your biggest hero deserves a special day when you can express your thanks and let him know 1.__________ important he is to you.The third Sunday of June – which 2.__________(fall) on June 19 this year – is Father’s Day.The idea of Father’s Day came from【小题3__________ American woman called Sonora Smart Dodd in 1909. Dodd wanted a special day 3.__________(honor) her father. He raised six children by 4.__________ after his wife died. Dodd thought there needed to be a day to honor loving dads.The first Father’s Day 5.__________(celebrate) on June 19, 1910. In 1924, US President Calvin Coolidge supported the idea of a 6.__________(nation) Father’s Day. Finally, in 1966, President Lyndon Johnson declared the third Sunday of June 7.__________ Father’s Day.Here are some ways to show your love and respect:* Send him a greeting card. Fathers prefer cards 8.__________ are not too emotional. So choose one that will make him laugh.* If he has a computer, cover his desktop 9.__________ words like “I love you Dad”.* A small present, such as a framed photo of your family, can make him feel like a king.