Answer 4.4:6
From Förberedande kurs i matematik 1
a) | \displaystyle x=n\pi | b) | \displaystyle \left\{\eqalign{
x&=\displaystyle \frac{\pi}{4}+2n\pi\cr x&=\displaystyle \frac{\pi}{2}+n\pi\cr x&=\displaystyle \frac{3\pi}{4}+2n\pi}\right. |
c) | \displaystyle \left\{\eqalign{
x&=\displaystyle \frac{2n\pi}{3}\cr x&=\displaystyle \pi + 2n\pi\cr }\right. |