Question

Rezultatul calculului arctg(1/9)+arctg(4/5) este ?

Answer 1

Este data formula:

arctg x+arctg y=arctg(x+y)/(1-xy) , daca x*y<1

arctg(1/9)+arctg(4/5) =arctg(1/9+4/5)/(1-1/9*4/5)=

=arctg((5+9)/45)/(1-4/45)=arctg(14/45)/(41/45)=

=arctg(14/45*45/41)=arctg(14/41)