Question

ctg t / (tg t + ctg t)=cos2t  - решите, пожалуйста ))

Answer 1

cos(t)/sin(t)*1/(sin(t)/cos(t)+cos(t)/sin(t))=cos(2t)

(cos(t))^2=cos(2t)
(sin(t))^2=0
sin(t)=0
t = n*pi