Ctg a = 3 ; 0 < a < П / 2 . знайти tg 2 a , ctg 2 a

1)tg(2a)=2*tg(a)/(1-tg²(a))=(2*1/3)/(1-(1/3)²)=(2/3)/(8/9)=3/4=0,752)ctg(2a)=1/tg(2a)=4/3=1+(1/3)