利用两角和(差)大的余弦公式化简
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/08/05 10:50:26
利用两角和(差)大的余弦公式化简
cos58°cos37°+sin58°sin37°
cos(60°+)-cos(60°-θ)
cos(60°+θ)+cos(60°-θ)
cos58°cos37°+sin58°sin37°
cos(60°+)-cos(60°-θ)
cos(60°+θ)+cos(60°-θ)
![利用两角和(差)大的余弦公式化简](/uploads/image/z/19020857-41-7.jpg?t=%E5%88%A9%E7%94%A8%E4%B8%A4%E8%A7%92%E5%92%8C%EF%BC%88%E5%B7%AE%EF%BC%89%E5%A4%A7%E7%9A%84%E4%BD%99%E5%BC%A6%E5%85%AC%E5%BC%8F%E5%8C%96%E7%AE%80)
cos58°cos37°+sin58°sin37°
=cos(58-37)=cos22
cos(60°+θ)-cos(60°-θ)
=-2sin60sinθ=-3^0.5sinθ
cos(60°+θ)+cos(60°-θ)
=2cos60cosθ=cosθ
=cos(58-37)=cos22
cos(60°+θ)-cos(60°-θ)
=-2sin60sinθ=-3^0.5sinθ
cos(60°+θ)+cos(60°-θ)
=2cos60cosθ=cosθ