1.
sin0° ;cos90°
2.
cos45°=√2/2
√8/4=2*√2/4=√2/2
cos135° =cos(180°-45° )=-cos45°=-√2/2
sin135° =sin(90°+45°)=cos45°=√2/2
−cos135° =−cos(180°-45° )=cos45°=√2/2