Алгебраические формулы

=±Ö1-sin2a=(1-tg2a/2)/(1+tg2a/2)
sina=±Ö1/1+ctg2a=(2tga/2)/(1+tg2a/2)

cos(ab)=sinasinbcosacosb
sin(a±b)=sinacosb±sinbcosa

tg(a+b)=sin(a+b)/cos(a+b)=(tga+tgb)/(1-tgatgb)
tg(a-b)=(tga-tgb)/(1+tgatgb)

ctg(a+b)=(ctgactgb-1)/(ctga+ctgb)
ctg(a-b)=(ctgactgb+1)/(ctgb-ctga)

sin2a=2sinacosa=(2tga)/(1+tg2a)
cos2a=cos2a-sin2a=(1-tg2a)/(1+tg2a)=2cos2a-1=1-2sin2a

tg2a=2tga/(1-tg2a) ctg2a=(ctg2a-1)/2ctga
ctg2a=(ctg2a-1)/2ctga

cos2a/2=1+cosa/2 cos2a=(1+cos2a)/2
sin2a/2=1-cosa/2 sin2a=(1-cos2a)/2

cosa/2=±Ö1+cosa/2
sina/2=±Ö1-cosa/2

tga/2=±Ö1-cosa/1+cosa=(sina)/(1+cosa)=(1-cosa)/sina
ctga/2=±Ö1+cosa/1-cosa=sina/(1-cosa)=(1+cosa)/sina

sina+cosa=Ö2 cos(P/4-a)
sina-cosa=Ö2 sin(a-P/4)

cosa-sina=Ö2 sin(P/4-a)
cosa+cosb=2cos(a+b)/2cos(a-b)/2

cosa-cosb=-2sin(a+b)/2sin(a-b)/2
sina+sinb=2sin(a+b)/2cos(a-b)/2

sina-sinb=2sin(a-b)/2cos(a+b)/2
tga±tgb=(sin(a±b))/cosacosb

cosacosb=1/2(cos(a-b)+cos(a+b))
sinasinb=1/2(cos(a-b)-cos(a+b))

sinacosb=1/2(sin(a+b)+sin(a-b))
tga=(2tga/2)/(1-tg2a/2)

cosa=±Ö1-sin2a=(1-tg2a/2)/(1+tg2a/2)
sina=±Ö1/1+ctg2a=(2tga/2)/(1+tg2a/2)

cos(ab)=sinasinbcosacosb
sin(a±b)=sinacosb±sinbcosa

tg(a+b)=sin(a+b)/cos(a+b)=(tga+tgb)/(1-tgatgb)
tg(a-b)=(tga-tgb)/(1+tgatgb)

ctg(a+b)=(ctgactgb-1)/(ctga+ctgb)
ctg(a-b)=(ctgactgb+1)/(ctgb-ctga)

sin2a=2sinacosa=(2tga)/(1+tg2a)
cos2a=cos2a-sin2a=(1-tg2a)/(1+tg2a)=2cos2a-1=1-2sin2a

tg2a=2tga/(1-tg2a) ctg2a=(ctg2a-1)/2ctga
ctg2a=(ctg2a-1)/2ctga

cos2a/2=1+cosa/2 cos2a=(1+cos2a)/2
sin2a/2=1-cosa/2 sin2a=(1-cos2a)/2

cosa/2=±Ö1+cosa/2
sina/2=±Ö1-cosa/2

tga/2=±Ö1-cosa/1+cosa=(sina)/(1+cosa)=(1-cosa)/sina
ctga/2=±Ö1+cosa/1-cosa=sina/(1-cosa)=(1+cosa)/sina

sina+cosa=Ö2 cos(P/4-a)
sina-cosa=Ö2 sin(a-P/4)

cosa-sina=Ö2 sin(P/4-a)
cosa+cosb=2cos(a+b)/2cos(a-b)/2

cosa-cosb=-2sin(a+b)/2sin(a-b)/2
sina+sinb=2sin(a+b)/2cos(a-b)/2

sina-sinb=2sin(a-b)/2cos(a+b)/2
tga±tgb=(sin(a±b))/cosacosb

cosacosb=1/2(cos(a-b)+cos(a+b))
sinasinb=1/2(cos(a-b)-cos(a+b))

sinacosb=1/2(sin(a+b)+sin(a-b))
tga=(2tga/2)/(1-tg2a/2)