$sin\alpha$ :

$sin0 = 0$

$sin\frac{\pi}{6}=\frac{1}{2}$

$sin\frac{\pi}{4} = \frac{\sqrt{2}}{2}$

$sin\frac{\pi}{3} = \frac{\sqrt{3}}{2}$

$sin\frac{\pi}{2} = 1$

$sin\pi = 0$

$sin\frac{3}{2}\pi = -1$

$sin2\pi = 0$

$cos\alpha$：

$cos0 = 1$

$cos\frac{\pi}{6}=\frac{\sqrt{3}}{2}$

$cos\frac{\pi}{4} = \frac{\sqrt{2}}{2}$

$cos\frac{\pi}{3} = \frac{1}{2}$

$cos\frac{\pi}{2} = 0$

$cos\pi = -1$

$cos\frac{3}{2}\pi = 0$

$cos2\pi = 1$

$tan\alpha$：

$tan0 = 0$

$tan\frac{\pi}{6}=\frac{\sqrt{3}}{3}$

$tan\frac{\pi}{4} = 1$

$tan\frac{\pi}{3} = \sqrt{3}$

$tan\frac{\pi}{2} = \nexists$

$tan\pi = 0$

$tan\frac{3}{2}\pi = \nexists$

$tan2\pi = 0$

$cot\alpha$：

$cot0 = \nexists$

$cot\frac{\pi}{6}=\sqrt{3}$

$cot\frac{\pi}{4} = 1$

$cot\frac{\pi}{3} = \frac{\sqrt{3}}{3}$

$cot\frac{\pi}{2} = 0$

$cot\pi = \nexists$

$cot\frac{3}{2}\pi = 0$

$cot2\pi = \nexists$