数学问题关于加法定理1/2sinA-√3/2cosA与sinA√2/2+cosA×cos7/4pi分别如何化简要过程_数学解答

数学问题关于加法定理
1/2sinA-√3/2cosA与sinA√2/2+cosA×cos7/4pi分别如何化简要过程

人气：268 ℃　时间：2020-06-19 21:33:43

解答

1/2sinA-√3/2cosA
=sinAcos(π/3)-cosAsin(π/3)
=sin(A-π/3)
sinA√2/2+cosA×cos(7π/4)
=sinAsin(π/4)+cosAcos(2π-π/4)
=sinAsin(π/4)+cosAcos(π/4)
=cos(A-π/4)