Question

помогите, пожалуйста

Answer 1

$\star \; cos(13,5\pi +6)=cos(14\pi -\frac{\pi}{2}+6)=cos(-\frac{\pi }{2}+6)=cos(\frac{\pi}{2}-6)=sin6\\\\\star \; ctg(17,5\pi -3)=ctg(18\pi -\frac{\pi}{2}-3)=ctg(-\frac{\pi}{2}-3)=ctg(-(\frac{\pi }{2}+3))=\\\\=-ctg(\frac{\pi}{2}+3)=-(-tg3)=tg3\\\\\star \; \sqrt{9-6\pi +\pi ^2}=\sqrt{\pi ^2-6\pi +9}=\sqrt{(\pi -3)^2}=|\underbrace {\pi -3}_{>0}|=\pi -3\\\\\star \; sin(\pi -3)=sin3\\\\\star \; cos(\pi -3)=-cos3\\\\\star \; sin3\cdot cos3=\frac{1}{2}sin6\\\\\\\frac{cos(13,5\pi +6)\cdot ctg(17,5\pi -3)}{sin(\sqrt{9-6\pi +\pi ^2})\cdot cos(\sqrt{\pi ^2-6\pi +9})}=\frac{sin6\cdot \frac{sin3}{cos3}}{sin(\pi -3)\cdot cos(\pi -3)}=\frac{2\cdot sin3\cdot cos3\cdot tg3}{-sin3\cdot cos3}=-2\cdot tg3$