Question

вычислить
arcCos(Cos(11 П/8));

Answer 1

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