f(x)=2a(cosx)^2+bsinxcosx-√3/2
f(0)=2a-√3/2=√3/2,a=√3/2
f(π/4)=a+b/2-√3/2=1/2,b=1
f(x)=√3(cosx)^2+sinxcosx-√3/2=sin(2x+π/3)
f(x)向右平移π/6长度变奇函数