在数学题目中常会遇到求极值问题,题目类型很多,解法也不少,利用跟的判别式也能解决其中许多类型的题目。函数y=f(x)的最大值和最小值与函数的值域有关。若a≤y≤b,则y的最小值为a,最大值为b;若y≤a或y≥b,则y的极大值为a,极小值为b;若y≤a,则y的最 In mathematics topics often encounter extreme value problems, many types of questions, many solutions, the use of the discriminant can solve many of these types of topics. The maximum and minimum values ​​of the function y = f (x) are related to the value range of the function. If a≤y≤b, the minimum value of y is a and the maximum value is b; if y≤a or y≥b, the maximum value of y is a and the minimum value is b; if y≤a, then y the most