论文部分内容阅读
问题发现,推敲问题文献[1]原文摘录如下:已知a,b和角B,常常可对角B应用余弦定理,并将其整理为关于c的一元二次方程c~2-2accos B+a·2-b~2=0,若该方程无解或只有负数解,则该三角形无解;若方程有一个正数解,则该三角形有一解;若方程有两个不等的正数解,则该三角形有两解,这样的观念是错误的.笔者认为以上论断不正确,其实这种观念是正确的,文献[1]通过例2,例3两个具体题目,利用余弦定
The problem is found, consider [1] the original extract is as follows: Known a, b and angle B, often cosine B can be applied to the diagonal B, and arranged into quadratic equations on c c ~ 2-2accos B + a · 2-b ~ 2 = 0. If the equation has no solution or only negative solution, the triangle has no solution. If the equation has a positive solution, then the triangle has a solution. If the equation has two unequal positive numbers Solution, then the triangle has two solutions, so the concept is wrong.I think the above conclusion is not correct, in fact, this concept is correct, the literature [1] through Example 2, Example 3 two specific topics, the use of cosine