Question

ctg(a+b)=-1/5 ctgb=2 ctga=?​

Answer 1

Answer:

Tga=4/3 tgb=7

tg(a+b)=(tga+tgb)/(1-tga*tgb)=(4/3+7):(1-4/3*7)=25/3:(-26/3)=-1

a+b=-π/4+πn,n∈Z