Question

Demonstrati:$\frac{tga+tgb}{tg(a+b)} - \frac{tga-tgb}{tg(a-b)} =-2tga*tgb$

Answer 1

tg(a+b)=tg(a+b) * 1/ (1-tga* tgb)
tg(a-b)=(tga-tgb) * 1/(1+tga*tgb)
P.S: inlocuieste si se va simplfica si e simplu..