Answer:
Check the proof below
Step-by-step explanation:
try to verify from RHS to LHS
(Tan a + tan b) / (tan a - tan b)
= (sin a / cos a + sin b /cos b) / ( sin a/ cos a - sin b/ cos b)
= (sin a cos b + cos a sin b)/ (sin a cos b - cos a sin b)
= sin (a+b) / sin (a-b)
Fyi
sin(A+B) = sinAcosB+cosAsinB
sin(A-B) = sinAcosB-cosAsinB
