cos2x+cos(x+π/3)+sin(x+π/6)+3sin^2x=cos2x+1/2*cosx-根号3/2*sina+根号3/2*sinx+1/2*cosx+3sin^2x=cos2x+cosx+3sin^2x=1-2sin^2x+cosx+3sin^2x=1+sin^2x+cosx=-cosx^2+cosx+2=-(cosx-1/2)^2+9/4当cosx=-1时,所取...