Question

Ctg 3a - tg 3a = выразите

Answer 1

$ctg 3a-tg 3a= frac{cos 3a}{sin 3a} - frac{sin 3a}{cos3a}= frac{cos^2 3a-sin^2 3a}{sin3a*cos3a}= frac{cos 6a}{ frac{1}{2}sin 6a } =2ctg 6a$