设半径为R,圆心角为α则周长=αR+2R=16,即α=(16-2R)/R则αR²=16R-2R²扇形面积=α/2π×πR²=αR²/2=(16R-2R²)/2=8R-R²=-(R-4)²+16∴当R=4时,扇形面积最大此时,圆心角α=(16-2R)...