若cos(α+π/6)-sinα=(3√3)/5,则cos(α+π/3)=___
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若cos(α+π/6)-sinα=(3√3)/5,则cos(α+π/3)=___
![若cos(α+π/6)-sinα=(3√3)/5,则cos(α+π/3)=___](/uploads/image/z/15363410-50-0.jpg?t=%E8%8B%A5cos%28%CE%B1%2B%CF%80%2F6%29-sin%CE%B1%3D%EF%BC%883%E2%88%9A3%EF%BC%89%2F5%2C%E5%88%99cos%28%CE%B1%2B%CF%80%2F3%29%3D___)
用a吧
cosacosπ/6-sinasinπ/6-sina=3√3/5
cosa*√3/2-sina*1/2-sina=3√3/5
cosa*√3/2-sina*3/2=3√3/5
两边除以√3
cosa*1/2-sina*√3/2=3/5
cosacosπ/3-sinasinπ/3=3/5
所以cos(a+π/3)=3/5
cosacosπ/6-sinasinπ/6-sina=3√3/5
cosa*√3/2-sina*1/2-sina=3√3/5
cosa*√3/2-sina*3/2=3√3/5
两边除以√3
cosa*1/2-sina*√3/2=3/5
cosacosπ/3-sinasinπ/3=3/5
所以cos(a+π/3)=3/5
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