(1) sin450°=sin90°=1\sin 450° = \sin 90° = 1sin450°=sin90°=1 (2) sin(−765°)=sin(−45°)=−12\sin(-765°) = \sin(-45°) = -\frac{1}{\sqrt{2}}sin(−765°)=sin(−45°)=−21 (3) cos2130°=cos330°=32\cos 2130° = \cos 330° = \frac{\sqrt{3}}{2}cos2130°=cos330°=23 (4) cos(−120°)=−12\cos(-120°) = -\frac{1}{2}cos(−120°)=−21 (5) tan420°=tan60°=3\tan 420° = \tan 60° = \sqrt{3}tan420°=tan60°=3 (6) tan(−225°)=−1\tan(-225°) = -1tan(−225°)=−1