Question

вычислить
arcCos(Cos(11 П/8));

Answer 1

$arcCos(Cos(\frac{11\pi }{8}))=arcCos(Cos( \pi +\frac{3\pi }{8}))=arcCos(-Cos\frac{3\pi }{8})=\pi -arcCos(Cos\frac{3\pi }{8})=\pi-\frac{3\pi }{8}=\frac{5\pi}{8}$