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sin(90°+α)=cos α

sin(90°−α)=cos α

cos(90°+α)= -sin α

cos(90°−α)=sin α

sin(180°−α)=sin α

cos(180°−α)= −cos α

tg(90°+α)= -ctg α

tg(90°-α)=ctg α

sin 30°=1/2

sin 60°=√3/2

cos 30°=√3/2

cos 60°=1/2

tg 30°=1/2 : √3/2=1/√3=√3/3

tg 60°=√3/2 : 1/2=√3

ctg 30°=√3/2 : 1/2=√3

ctg 60°=1/2 : √3/2=√3/3

sin 45°=√2/2

cos 45°=√2/2

tg 45°=√2/2 : √2/2=1

ctg 45°=√2/2 : √2/2=1

Վարժ․ 303

1) 120°

sin 120°=sin(90°+α)=cos 30°

cos 30°=√3/2

cos(90°+α)= -sin α= -sin 30°

-sin 30°= -1/2

tg 120°=√3/2 : (-1/2)= -√3

2) 135°

sin 135°=sin(90°+α)=cos 45°

cos 45°=√2/2

cos(90°+α)= -sin α= -sin 45°

-sin 45°= -√2/2

tg 135°=√2/2 : (-√2/2)= -1

3) 150°

sin 150°=sin(90°+α)=cos 60°

cos 60°=1/2

cos(90°+α)= -sin α= -sin 60°

-sin 60°= -√3/2

tg 150°=1/2 : (-√3/2)= -√3/3