化简:(cos15度sin9度+sin6度)/(sin15度sin9度-cos6度)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

来源:学生作业帮助网 编辑:作业帮 时间:2024/03/29 17:28:13
化简:(cos15度sin9度+sin6度)/(sin15度sin9度-cos6度)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

化简:(cos15度sin9度+sin6度)/(sin15度sin9度-cos6度)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
化简:(cos15度sin9度+sin6度)/(sin15度sin9度-cos6度)
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
中的
=sin15cos9/(-cos15cos9)这一步到
=sin15/cos15
是怎么得到的?用的什么公式?

化简:(cos15度sin9度+sin6度)/(sin15度sin9度-cos6度)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
=sin15cos9/(-cos15cos9)这一步到(分子、分母都除以cos9 得到的)
应该是=-sin15/cos15