Question

tg(a-7п/2) если tg a=2

Answer 1

$tg(\alpha-\frac{7\pi }{2})=-tg(\frac{7\pi }{2}-\alpha)=-tg(3\pi+(\frac{\pi }{2}-\alpha))=-tg(\frac{\pi }{2}-\alpha)=\\\\=-Ctg\alpha=-\frac{1}{tg\alpha}=-\frac{1}{2}=\boxed{-0,5}$