已知函数f(x)=sinx+sin(x+180/2),R(1)求f(x)的最小正周期(2)若f(x)=3/4,求sin2

f(x）=sinx sin(x π/2)=sinx cosx 故f(x)的最小正周期是2π f^2(x）=(sinx cosx)^2=1 sin2x sin2x=-7/16 sin(x π/2)=cosx f