It is known that the values of sinx repeat after an interval of 2π or 360°.∴sin(11π/3) = sin(11π/3 + 2 × 2π) = sin(11π/3 + 4π) = sin(23π/3) = sin(8π - π/3) = sin(-π/3) = -sin(π/3) = -√3/2