不等式的恒成立问题是学生较难理解和掌握的一个难点 ,以数列为载体的不等式恒成立问题的综合性更强 ,是高三第二轮复习中不可多得的一个专题 .例 1　 ( 2 0 0 3年新教材高考题改编题 )设a0 为常数 ,数列 {an}的通项公式为 an =15.[3n + ( - 1 ) n-1.2 n]+ ( - 1 ) n .2 na0 　 The constant establishment of inequality is a difficult problem for students to comprehend and master. The comprehensive problem of establishing the inequality of series-based inequalities is more comprehensive. It is a rare topic in the second round of review of the third year. Example 1 (2 0 0 3 years new textbooks college entrance examination questions reorganized question) Let a0 be a constant, the general formula of the series {an} is an = 15. [3n + (-1) n-1.2 n] + (-1) n .2 na0