sina^2+cosa^2=1;
sina/cosa=tana;
tanacota=1;
sin(180+a)=-sina;
cos(180+a)=-cosa;
sin(-a)=-sina;
cos(-a)=cosa;
sin(180-a)=sina;
cos(180-a)=-cosa;
sin(360-a)=-sina;
cos(360-a)=cosa;
cos(a+b)=cosacosb-sinasinb;
cos(a-b)=cosacosb+sinasinb;
cos(90-a)=sina;
sin(90-a)=cosa;
sin(a+b)=sinacosb+cosasinb;
sin(a-b)=sinacosb-cosasinb;
tan(a+b)=tana+tanb/1-tanatanb
tan(a-b)=tana-tanb/1+tanatanb
sin2a=2sinacosa
cos2a=cosa^2-sina^2
tan2a=2tana/1-tana^2
cos2a=1-2sina^2
cos2a=2cosa^2-1