题目

已知函数y＝x3－3x＋c的图象与x轴恰有两个公共点，则c＝________. 答案：－2或2解析 设f(x)＝x3－3x＋c，对f(x)求导可得， f′(x)＝3x2－3，令f′(x)＝0，可得x＝±1. 易知f(x)在(－∞，－1)，(1，＋∞)上单调递增，在(－1,1)上单调递减． 若f(1)＝1－3＋c＝0，可得c＝2. 若f(－1)＝－1＋3＋c＝0，可得c＝－2. 根据句意及首字母，写出单词，使句子意思完整 1．My m________ birthday is December 13th. 2．I like p________ music. 3．She w ________ to play baseball. 4．The little boy wants some c________. 5．Miss Wang is o________ music teacher. 6．Do you want to play with the dog n________ ? 7．Let's p________ games. 8．Tom is Mary's boy f________. 9．I want to put the things i________ the box. 10．Would you like to come to my birthday p________ ?