已知cos(π/3-α)=根号3/3,求cos(2π/3+α)+cos2(7π/6+α)
答案:2 悬赏:70 手机版
解决时间 2021-03-06 07:00
- 提问者网友:杀手的诗
- 2021-03-05 18:59
已知cos(π/3-α)=根号3/3,求cos(2π/3+α)+cos2(7π/6+α)
最佳答案
- 五星知识达人网友:十年萤火照君眠
- 2021-03-05 19:39
cos(π/3-α)=√3/3cos(2π/3+α)+cos2(7π/6+α)=-cos(π-(2π/3+α)) + cos(7π/3 +2α)=-cos(π/3-α) + cos(π/3 +2α)=-√3/3 - cos(2π/3-2α)=-√3/3 - cos2(π/3-α)=-√3/3 - 2[cos(π/3-α)]^2 +1=-√3/3 - 2(1/3) + 1=-√3/3 + 1/3======以下答案可供参考======供参考答案1:∵cos(π/3-α)=根号3/3cos(2π/3+α)=cos[π-(π/3-α)]=-cos(π/3-α)=-√3/3cos(7π/6+α)=cos[π/2+(2π/3+α)]=-sin(2π/3+α)=-√(1-1/3)=-√6/3∴cos2(7π/6+α)=2[cos(7π/6+α)]^2--1=1/3∴cos(2π/3+α)+cos2(7π/6+α)=-√3/3+1/3
全部回答
- 1楼网友:掌灯师
- 2021-03-05 20:51
回答的不错
我要举报
如以上回答内容为低俗、色情、不良、暴力、侵权、涉及违法等信息,可以点下面链接进行举报!
点此我要举报以上问答信息
大家都在看
推荐资讯