sin多少度角等于0.5？sinA=0.5因为A=（π/6）+2kπ, k属于整数所以, sin(（π/6）+2kπ)=0.5, k属于整数举例：sin30°=0.5sin150°=0.5角度制与弧度制不能混用。
解:因为.arcsin0.5=30°+2kπ, k属于整数所以, sin(30°+2kπ)=0.5, k属于整数
