化简cos(α- 5π/3)+cos(α+13π/3)
问题描述:
化简cos(α- 5π/3)+cos(α+13π/3)
答
cos(α- 5π/3)+cos(α+13π/3)
=cos(α+2π- 5π/3)+cos(α+13π/3-4π)
=cos(α+ π/3)+cos(α+π/3)
=2cos(α+π/3)