中职数学基础模块上册的一道习题:现有长7米的材料,要制作如图的“目”字形窗框,为使透过的光最大,则其中一边应取何值?此时,窗框的面积为多少?一般先让学生做,然后讲评,最后订正。第二次将“目”字改为“日”字,作为单元考试的试题。也是让学生做,然后讲评,最后订正。第三次将“目”字改为“皿”字,作为期末考试的试题。但确有80%的同学不会做,这让我 The math basic module on the book on a book exercise: the existing 7-meter-long material, as shown in the picture to make “” mesh “shaped window frame, in order to maximize the light through, which side should take what? What is the area of ​​the window frame? Generally let the students do first, and then comment on the final revision. The second will be ”head “ word to ”day “ word, as a unit test questions. It is also for students to do, then comment, finally revised. The third time, ”head “ to ”" words, as the final exam questions. But 80% of students do not do it, which makes me