Question

помогите пожалуйста 30 баллов

Answer 1

Ответ:

$tg585^\circ =tg(360^\circ +225^\circ )=tg225^\circ =tg(270^\circ -45^\circ )=ctg45^\circ =1\\\\\\ctg\dfrac{13\pi }{6}=ctg\Big(2\pi +\dfrac{\pi}{6}\Big)=ctg\dfrac{\pi}{6}=\sqrt3\\\\\\sin(-675^\circ )=sin(-720^\circ +45^\circ )=sin45^\circ =\dfrac{\sqrt2}{2}\\\\\\cos\dfrac{9\pi }{4}=cos\Big(2\pi +\dfrac{\pi}{4}\Big)=cos\dfrac{\pi}{4}=\dfrac{\sqrt2}{2}$