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已知tan(x+y)=2/5,tan(x-y)=-1/4,则tan2x的值是
人气:258 ℃ 时间:2020-06-02 18:30:04
解答
tan2x=tan [(x+y)+(x-y)]
=[tan(x+y)+tan(x-y)]/[1-tan(x+y)tan(x-y)]
=3/22
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