π/2

2kπ+π π/2 π/2 -π/2 π/2 -π/2 -π/2 π/2 π/2 π/2 π/2 2/π π/2 kπ-2π/3 已知π+2Kπ Sin(π+π/6)Sin(2π+π/6)Sin(3π+π/6).Sin(2008π+π/6)求值 设2kπ+π/2 为什么=2Kπ+π/2