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若2sinx+3cosx=0,则(sin^2x+sin2x)/(cos^2x)
人气:194 ℃ 时间:2020-07-02 01:06:04
解答
2sinx+3cosx=0
sinx/cosx=-3/2=tanx
(sin^2x+sin2x)/(cos^2x)
=(sin^2x+2sinxcosx)/(cos^2x) (上下同除以cos^2x)
=(tan^2x+2tanx)
=9/4-3
=-3/4
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