问题
下面【三角函数 $\sin$ 的特殊角数值】中，正确的是哪个？选项
[A]. $\sin 0$ $=$ $1$ $\color{White}{//}$ $\sin \frac{\pi}{6}$ $=$ $\frac{1}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{4}$ $=$ $\frac{\sqrt{2}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{3}$ $=$ $\frac{\sqrt{3}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{2}$ $=$ $1$[B]. $\sin 0$ $=$ $0$ $\color{White}{//}$ $\sin \frac{\pi}{6}$ $=$ $\frac{1}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{4}$ $=$ $\frac{\sqrt{2}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{3}$ $=$ $\frac{\sqrt{3}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{2}$ $=$ $0$
[C]. $\sin 0$ $=$ $0$ $\color{White}{//}$ $\sin \frac{\pi}{6}$ $=$ $\frac{1}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{4}$ $=$ $\frac{\sqrt{2}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{3}$ $=$ $\frac{\sqrt{3}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{2}$ $=$ $1$
[D]. $\sin 0$ $=$ $0$ $\color{White}{//}$ $\sin \frac{\pi}{6}$ $=$ $\frac{1}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{4}$ $=$ $\frac{\sqrt{2}}{3}$ $\color{White}{//}$ $\sin \frac{\pi}{3}$ $=$ $\frac{\sqrt{3}}{2}$ $\color{White}{//}$ $\sin \frac{\pi}{2}$ $=$ $1$
$\sin 0$ $=$ $0$ $\color{Red}{//}$ $\sin \frac{\pi}{6}$ $=$ $\frac{1}{2}$ $\color{Red}{//}$ $\sin \frac{\pi}{4}$ $=$ $\frac{\sqrt{2}}{2}$ $\color{Red}{//}$ $\sin \frac{\pi}{3}$ $=$ $\frac{\sqrt{3}}{2}$ $\color{Red}{//}$ $\sin \frac{\pi}{2}$ $=$ $1$