答案解析

查看更多优质解析解答一举报tana=对边比邻边tana=sina/cosatan(a+b)=)=(tan(a)+tan(b))/(1-tan(a)tan(b)) tan(a-b)=[tan(a)-tan(b)]/[1 tan(a)tan(b)]tan2A=2tanA/(1-tan2A)tana=2tan(a/2)/[1-tan²(a/2)]

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