设a＞0为常数,已知函数f(x)=cos平方(x-2π/3)+sin平方(x-5π/6)+asinx/2cosx/2的最大值为2,求a的值.

f(x)=(cos(x-2π/3))^2+(sin(x-5π/6))^2+asin(x/2)cos(x/2)=(cosx*cos(2π/3)+sinx*sin(2π/3))^2+(sinxcos(5π/6)-cosxsin(5π/6))^2+a/2*sinx=(-1/2*cosx+√3/2*sinx)^2+(-√3/2*sinx-1/2*cosx)^2+a/2*sinx=1/4*(...