(π/2-α)=cosα tg(π/2-α)=ctgα cos(π/2-α)=sinα ctg(α-π)=ctgα tg(α-π)=tgα cos(3/2π-α)=-sinα sin(α-3/2π)=cosα cos(π+α)=-cosα 118 sinα=210°=-1/2 cosα=210°=-√3/2 tgα=210°=√3/3 ctgα=210°=√3 sinα=5/4π=225°=-√2/2 cosα=5/4π=225°=-√2/2 tgα=5/4π=225°=1 ctgα=5/4π=225°=1 sinα=4/3π=240°=-√3/2 cosα=4/3π=240°=-1/2 tgα=4/3π=240°=√3 ctgα=4/3π=240°=√3/3 119 ctg(90°-α)=tgα cos(90°+α)=-sinα sin(270°-α)=-cosα sin(270°+α)=cosα tg(α-270°)=-ctgα ctg(α-180°)=ctgα 120 cos(810°+α)=- sinα cos(990°-α)=- cosα tg(α-450°)=- ctgα tg(7π-α)=-tgα 121 cos²(3π/2-x)=0+sin²(x)=sin²(x) tg²(π+x)=tg²π+tg²x=tg²x cos4(π-x)=-cos4(x)=cos4x 122 ա) sin²(180°-α)+sin²(270°-α)=sin²α+(-cos²α)=sin²α+cos²α=1բ) sin(90°-α)+cos(180°+α)+tg(270°-α)+ctg(360°+α)=sin(90°-α)+cos(180°+α)-ctg α+ctg α=0գ) sin(π+α)cos(π/2+α)-cos(2π+α)sin(3π/2-α)=-sin α×(-sin α)-cos α×(-cos α)=sin²α+cos²α=1դ) tg α