cos660°的值为(  )A.?12B.?32C.12D.3

cos660°的值为(  )A.?12B.?32C.12D.32
2025-06-27 16:07:22
推荐回答(1个)
回答1:

cos660°=cos(720°-60°)=cos(-60°)=cos60°=

1
2

故选:C.