作业帮求：“积化和差,和差化积”公式!
来源：学生作业帮 编辑：拍题作业网作业帮 分类：数学作业 时间：2024/04/28 12:00:05
求：“积化和差,和差化积”公式!
sinθ+sinφ=2sin(θ/2+θ/2)cos(θ/2-φ/2)
sinθ-sinφ=2cos(θ/2+φ/2)sin(θ/2-φ/2)
cosθ+cosφ=2cos(θ/2+φ/2)cos(θ/2-φ/2)
cosθ-cosφ=-2sin(θ/2+φ/2)sin(θ/2-φ/2)
sinαsinβ=-1/2[cos(α+β)-cos(α-β)]
cosαcosβ= 1/2[cos(α+β)+cos(α-β)]
sinαcosβ= 1/2[sin(α+β)+sin(α-β)]
cosαsinβ= 1/2[sin(α+β)-sin(α-β)]
sinθ-sinφ=2cos(θ/2+φ/2)sin(θ/2-φ/2)
cosθ+cosφ=2cos(θ/2+φ/2)cos(θ/2-φ/2)
cosθ-cosφ=-2sin(θ/2+φ/2)sin(θ/2-φ/2)
sinαsinβ=-1/2[cos(α+β)-cos(α-β)]
cosαcosβ= 1/2[cos(α+β)+cos(α-β)]
sinαcosβ= 1/2[sin(α+β)+sin(α-β)]
cosαsinβ= 1/2[sin(α+β)-sin(α-β)]