[sin330°-tan(-13π/3)]/[cos(-19π/6)-cos690°]
来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/06/13 09:09:31
[sin330°-tan(-13π/3)]/[cos(-19π/6)-cos690°]
sin(330°)=sin(330-360)=-sin30°=-1/2
tan(-13π/3)=-tan(13π/3)=-tan(4π+π/3)=-tan(π/3)=-根号3
cos(-19π/6)=cos(19π/6)=cos(2π+π+π/6)=-cos(π/6)=-根号3/2
cos690°=cos(720°-30°)=cos(-30°)=根号3/2
所以,原式
=(-1/2+根号3)/(-根号3)
=-1+根号3/6
不知您是否明白了哈,要有不明白欢迎再提问( ⊙ o ⊙ )啊!
tan(-13π/3)=-tan(13π/3)=-tan(4π+π/3)=-tan(π/3)=-根号3
cos(-19π/6)=cos(19π/6)=cos(2π+π+π/6)=-cos(π/6)=-根号3/2
cos690°=cos(720°-30°)=cos(-30°)=根号3/2
所以,原式
=(-1/2+根号3)/(-根号3)
=-1+根号3/6
不知您是否明白了哈,要有不明白欢迎再提问( ⊙ o ⊙ )啊!
[sin330°-tan(-13π/3)]/[cos(-19π/6)-cos690°]
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