答案:-1/4
由题得:4sin(a+π/6)+4cosa-根号3=0
展开后化简得:(2根号3)sina+6cosa=根号3
即:sina+(根号3)*cosa=1/2
而 sin(a+4π/3)=sina*cos4π/3+cosa*sin4π/3=(-1/2)*[sina+(根号3)*cosa]=-1/4
答案:-1/4
由题得:4sin(a+π/6)+4cosa-根号3=0
展开后化简得:(2根号3)sina+6cosa=根号3
即:sina+(根号3)*cosa=1/2
而 sin(a+4π/3)=sina*cos4π/3+cosa*sin4π/3=(-1/2)*[sina+(根号3)*cosa]=-1/4