cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,

来源:学生作业帮助网 编辑:六六作业网 时间:2024/05/14 19:19:07
cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,cos(a-b)cos(a+b)+sin(a-b)sin

cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,
cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,

cos(a-b)cos(a+b)+sin(a-b)sin(a+b)化简,
根据公式cos(A-B)=cosAcosB+sinAsinB可得
cos(a-b)cos(a+b)+sin(a-b)sin(a+b)
=cos[(a-b)-(a+b)]
=cos(-2b)
=cos2b