sin(α-β)怎么用cos(α-β)\cos(α+β)推导
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/03 11:21:17
![sin(α-β)怎么用cos(α-β)\cos(α+β)推导](/uploads/image/z/13052843-35-3.jpg?t=sin%28%CE%B1-%CE%B2%29%E6%80%8E%E4%B9%88%E7%94%A8cos%28%CE%B1-%CE%B2%29%5Ccos%28%CE%B1%2B%CE%B2%29%E6%8E%A8%E5%AF%BC)
sin(α-β)怎么用cos(α-β)\cos(α+β)推导
sin(α-β)怎么用cos(α-β)\cos(α+β)推导
sin(α-β)怎么用cos(α-β)\cos(α+β)推导
已知:
cos (α +β) = cos α cos β -sin α sin β,
sin (π/2 -α) =cos α,
cos (π/2 -α) =sin α.
则
sin (α -β) =cos [ π/2 -(α -β) ]
=cos [ (π/2 -α)+β ]
=cos (π/2 -α) cos β -sin (π/2 -α) sin β
=sin α cos β -cos α sin β.
= = = = = = = = =
sin (α +β) 可用 cos (α -β) 和诱导公式推导.