求证 cos（A）+ 根号3sin(A)=2sin(π/6+A)
问题描述：
求证 cos（A）+ 根号3sin(A)=2sin(π/6+A)
答
左边=2(√3/2*sinA+1/2*cosA)
=2(sinAcosπ/6+cosAsinπ/6)
=2sin(A+π/6)=右边
答
右边2sin(π/6+A)=2sin(π/6)cosA+2sinAcos(π/6)=cosA+根号3sin(A)=左式.得证#