Step 1: StartFraction sine (x minus y) Over cosine (x minus y) EndFraction
Step 2: StartFraction sine (x) cosine (y) + cosine (x) sine (y) Over (A) cosine (y) minus sine (x) sine (y) EndFraction
Step 3: StartStartFraction StartFraction sine (x) cosine (y) + cosine (x) sine (y) Over cosine (x) (B) EndFraction OverOver StartFraction cosine (x) cosine (y) minus sine (x) sine (y) Over cosine (x) cosine (y) EndFraction EndEndFraction
Step 4: StartStartFraction StartFraction sine (x) cosine (y) Over cosine (x) cosine (y) EndFraction + StartFraction cosine (x) sine Over cosine (x) cosine (y) EndFraction OverOver StartFraction cosine (x) cosine (y) Over cosine (x) cosine (y) EndFraction minus StartFraction sine (x) sine (y) Over cosine (x) cosine (y) EndFraction EndEndFraction
Step 5:
The work shown is a way to derive Tangent (x + y) = StartFraction tangent (x) + tangent (y) Over 1 minus tangent (x) tangent (y) EndFraction
What expressions go in the derivation of the tangent sum identity in place of A, B, and C?
