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幼苗
共回答了17个问题采纳率:82.4% 举报
(sin115+sin15sin10)/(sin155-cos15cos80)
=(sin65+sin15sin10)/(sin25-cos15cos80)
=[sin(90-25)+sin15sin10]/[sin(15+10)-cos15cos(90-10)]
=(cos25+sin15sin10)/(sin15cos10+cos15sin10-cos15sin10)
=[cos(15+10)+sin15sin10]/sin15cos10
=(cos15cos10-sin15sin10+sin15sin10)/sin15cos10
=cos15/sin15
=cot15
=tan75
=2+根号3
1年前
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