Homework Help: Trigonometry

Posted by AwesomeGuy on Thursday, February 21, 2013 at 10:35pm.

Verify the identities please.
1.) TAN(X+π)-TAN(π-X)= 2 TAN X

2.) SIN(X+Y)+SIN(X-Y)= 2 SIN X COS Y

Trigonometry - Reiny, Thursday, February 21, 2013 at 10:40pm
1. by the CAST rule
tan(π+Ų) = tanŲ
tan(π-Ų) = -tanŲ

LS = tan(x+π) - tan(π-x)
= 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, Thursday, February 21, 2013 at 10:48pm
AWESOME! SUPERB! I had it right when you provided support. THANKS!

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