来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/14 21:15:11
高一数学,14题,加步骤,谢谢
![](http://img.wesiedu.com/upload/9/46/9460b5cc6b40be0a28a74a30b903100d.jpg)
题目是 tan1234°=a,那么sin(-206°)+cos(-206°)的值为
tan1234=tan(8*180-206)=tan(-206)=a
sin(-206)/cos(-206)=a
sin(-206)=acos(-206)
[sin(-206)]^2+[cos(-206)]^2=1
sin(-206)=acos(-206)
[cos(-206)]^2=1/(a^2+1)
cos(-206)=-cos26