ctg=cos:sin                        sin
2
+cos
2
=1 sin2=2sincos 
tgctg=1                                 tg=sin:cos cos2=cos
2
-sin
2
=1-2sin
2
=2cos
2
-1
sin=2tg(/2):(1+tg
2
(/2))      1+tg
2
=1:cos
2
 tg2=2tg:(1-tg
2
)                 
cos=1-tg
2
(/2):(1+tg
2
(/2))   1+ctg
2
=1:sin
2
 ctg2=(ctg
2
-1):2ctg              
tg=2tg
2
(/2):(1-tg
2
(/2))        1-cos=2sin
2
/2 sin3=3sin-4sin
3
               
ctg=1-tg
2
(/2):2tg
2
(/2)         1+cos=2cos
2
/2 cos3=4cos
3
-3cos
sin
2
cos
2
=1/4sin
2
2                tg
2
=1-cos2:(1+cos2) tg3=3tg-tg
3
:(1-3tg
2
) 
sin
2
=(1-cos2):2                     ctg
2
=1+cos2:(1-cos2) ctg3=3ctg-ctg
3
:(1-3ctg
2
)  
cos
2
=(1+cos2):2                    1+sin=(sin/2+cos/2)
 2
sin+sin=2(sin(+):2)(cos(-):2)    sinsin=1/2(cos(-)-cos(+))
sin-sin= 2(sin(-):2)(cos(+):2)    coscos=1/2(cos(-)+cos(+))
cos+cos=2(cos(+):2)(cos(-):2)   sincos=1/2(sin(+)+sin(-))
cos-cos=-2(sin(+):2)(sin(-):2)   
tg+tg=sin(+):(coscos)       
ctg+ctg=sin(++):(sinsin)     
sin(+)=sincos+cossin tg(+)=tg+tg:(1-tgtg)
cos(+)=coscos-sinsin tg(-)=tg-tg:(1+tgtg)
cos(-)=coscos+sinsin ctg(+)=ctgctg+1:(ctg(+ctg))