论文部分内容阅读
《中小学数学》(初中版)2009年第9期刊登了姚炳华、周珣两位老师撰写的《谈三角形三边关系的教学》一文,仔细研读后,有些不同的看法.一、“能构成三角形”不等同于“是三角形”两位老师认为:“教学中,不少教师把三角形三边关系定理作为判定三线段能否构成三角形的依据,稍加分析可知这是一个错误的论证,前者题设是三角形,结论是任意两边之和大于第三边;后者题设是三线段关系,结论是这三线段能否构成三角形.所以,判定三线段能否构成三角形不属于三角形三边关系定理的应用范围,如同勾股定理不属于判定一个三角形是直角
”Primary and secondary mathematics“ (2009) ninth published in 2009, Yao Binghua, Zhou Yong two teachers wrote the ”talk about the triangular relationship between the teaching,“ a paper, after careful study, a little different views. Constitute a triangle ”not equal to “ is a triangle ”two teachers think: " teaching, many teachers of the triangle trilateral relationship theorem as a basis for determining whether the three-line segment can form a triangle, a little analysis shows that this is a Wrong argument, the former problem is set to the triangle, the conclusion is that the sum of any two sides is greater than the third side; the latter problem is the relationship between the three lines, the conclusion is that these three segments can form a triangle.Therefore, to determine whether the three-line segment can form a triangle Belongs to the application of the triangular relationship theorem, as Pythagorean theorem does not belong to determine a triangle is a right angle