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化简:(cos15度sin9度+sin6度)/(sin15度sin9度-cos6度)
人气:368 ℃ 时间:2019-11-06 13:16:20
解答
原式=[cos15sin9+sin(15-9)]/[sin15sin9-cos(15-9)]
=(cos15sin9+sin15cos9-cos15sin9)/(sin15sin9-cos15cos9-sin15sin9)
=sin15cos9/(-cos15cos9)
=sin15/cos15
=-tan15
=-tan(45-30)
=-(tan45-tan30)/(1+tan45tan30)
=-2+√3
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