Lösung 4.4:2f
Aus Online Mathematik Brückenkurs 1
Using the unit circle shows that the equation \displaystyle \cos 3x = -1/\!\sqrt{2} has two solutions for \displaystyle 0\le 3x\le 2\pi\,,
We obtain the other solutions by adding multiples of \displaystyle 2\pi,
i.e.
where n is an arbitrary integer.