已知sin(α+π/3)=√2/4,π/6＜α＜2π/3,则cos(2π/3 + α)=?
问题描述：
已知sin(α+π/3)=√2/4,π/6＜α＜2π/3,则cos(2π/3 + α)=?
答
∵π/6＜α＜2π/3
∴ π/2＜α+π/3＜π
∴ cos(α+π/3)