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已知tanx=3,则sin2x=
人气:201 ℃ 时间:2020-10-02 04:57:52
解答
sin2x
=2sinxcosx/1
=2sinxcosx/(sin^2x+cos^2x) 分子分母同时除以cos^2x
=2tanx/(tan^2x+1) 代入tanx=3
=6/10
=3/5
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