cos(π-α)=-1⼀2则cos(-2π-α)的值等于多少

2024-12-21 19:12:21
推荐回答(1个)
回答1:

解:
cos(π-α)=-cosα=-1/2
cosα=1/2
cos(-2π-α)=cos[-(2π+α)=cos(2π+α)=cosα=1/2
cos(-2π-α)=1/2