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+Ø) = tanØ

tan(π-Ø) = -tanØ

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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