Posted by AwesomeGuy on .
Verify the identities please.
1.) TAN(X+π)TAN(πX)= 2 TAN X
2.) SIN(X+Y)+SIN(XY)= 2 SIN X COS Y

Trigonometry 
Reiny,
1. by the CAST rule
tan(π+Ø) = tanØ
tan(πØ) = tanØ
LS = tan(x+π)  tan(πx)
= tanx  (tanx)
= 2tanx
= RS
2. again one of the standard identities used on the LS
LS = sinxcosy + cosxsiny + sinxcosy  cosxsiny
= 2sinxcosy
= RS
btw, 2sinxcosy = sin (2x) which would be a simplification of the RS 
Trigonometry 
AwesomeGuy,
AWESOME! SUPERB! I had it right when you provided support. THANKS!