题目已知sinαcosβ=1/4,则cosαsinβ的取值范围是.笔者在高三一轮复习中讲两角和、差的正弦、余弦及正切这节时遇到了这样一道试题,全班共计64名学生,只有10名学生正确,正确率显然不高.在讲评这道试题之前笔者对学生错误情况做了调查发现有如下两个原因:其一,题目条件少,无法形成有效的解题思路;其二,考虑问题不全面,给出了[-3/4,5/4]、[-5/4,3/4]的答案,导致失分.讲解时,笔者和学生一起对题目 Title known sinαcosβ = 1/4, cosαsinβ value range is the author in the high school round of reviewing the corners and corners, the sine, cosine and tangent this section encountered such a test questions, the class a total of 64 Students, only 10 students correct, the correct rate is obviously not high.After commenting on this test questions I did a survey of students’ error conditions for the following two reasons: First, the problem is less, can not form an effective problem solving ideas ; Second, consider the problem is not comprehensive, given the [-3 / 4,5 / 4], [- 5 / 4,3 / 4] answer, leading to loss of points.When explaining, I and the students together on the subject