Question

Найти тангенс альфа и котангенс альфа если А равен -13π/4

Answer 1

$\star \ \ tg\Big(-\dfrac{13\pi}{4}\Big)=tg\Big(-\dfrac{12\pi +\pi }{4}\Big)=tg\Big(-3\pi -\dfrac{\pi}{4}\Big)=-tg(3\pi +\dfrac{\pi}{4}\Big)=\\\\\\=-tg\Big(\pi +\dfrac{\pi}{4}\Big)=-tg\dfrac{\pi}{4}=-1\\\\\\\\\star \ \ ctg\Big(-\dfrac{13\pi }{4}\Big)=\dfrac{1}{tg(-\frac{13\pi}{4})}=\dfrac{1}{-1}=-1$