sin(x+y)= sinx cosy+siny cosx

cos(x+y)= cosx cosy-sinx siny

sin(x-y)= sinx cosy-siny cosx

cos(x-y)= cosx cosy+sinx siny

tg(x+y)=
tgx=

tg(x-y)=
ctgx=

ctg(x+y)=
tgx=

ctg(x-y)=
sin
x+cos
x=1

sin
=

cos
=

c a

tg
=

b ctg
=

a²+b²=c²