求y=sinxcos(2π/3-x)、y=sinx+sin(2π/3-x)的最大值和最小值
问题描述：
求y=sinxcos(2π/3-x)、y=sinx+sin(2π/3-x)的最大值和最小值
答
y=sinxcos(2π/3-x)、cosαsinβ=[sin(α+β)-sin(α-β)]/2y=[sin(2π/3-x+x)-sin(2π/3-x-x)]/2=(根号3)/4-1/2[sin(2π/3-2x)最大值=(根号3)/4+1/2 最小值=(根号3)/4-1/2 y=sinx+sin(2π/3-x)sinαsinβ=-[cos(α+...