利用导数证明不等式或求参数范围问题是近几年高考的一种热点题型,而解这类问题的真正难点是判断或讨论含单参数导函数的符号问题,本文结合具体实例阐述解这类问题的四种途径,仅供参考.一、依已知中参数的范围,去参后判断符号例1已知函数f(x)=(a+1)lnx+ax2+1,(1)讨论函数f(x)的单调性;(2)设a≤ The use of derivatives to prove the inequality or the problem of parameter range is a hot topic type in college entrance examination in recent years. The real difficulty in solving such a problem is to judge or discuss the problem of notation with a single parameter derivative function. In this paper, The four ways of the problem, for reference purposes only. First, according to the known parameters in the range, to judge after the reference parameters Example 1 known function f (x) = (a +1) lnx + ax2 +1, (1) Monotonicity of function f (x); (2) Let a ≤