已知三角形ABC中,a=根号2,b=2,A=30度,求B,C及c。

要有详细步骤,要用高中的方法解决!
2024-12-21 14:23:33
推荐回答(2个)
回答1:

好吧 我没办法传相片!先由正弦定理让a/b=sinA/sinB然后由于a和b是已知数,sin30为二分之一!即可算出sinB的值!根据三角形内角和为180可以算出C的值,为两个,一个是45,一个是135!然后根据余弦定理的变式将有关数据带进去即可算出正确结果!顺便说一句:这种题以后对高中的你是最简单的题,一定要把这种类型的题全部会做并且得做对,高三时你会发现如果这样的题都不会那么高考就没戏了!本人只是给个意见而已,刚参加过高考,切身体会,希望可以帮助到!

回答2:

由正弦定理a/b=sinA/sinB可得 根号2 比 2=1/2 比 sinB 得出B是45度或135度
再根据三角形内角和180度
①B是45度,则C是105度,由正弦定理得 a/c=sinA/sinC 剩下的不用我说了吧
②B是135度,则C是15度,同理吧

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