Answer 4.4:5
From Förberedande kurs i matematik 1
| a) | \displaystyle \left\{\eqalign{
x&=n\pi\cr x&=\displaystyle \frac{\pi}{4}+\displaystyle \frac{n\pi}{2} }\right. | b) | \displaystyle x=\displaystyle \frac{n\pi}{3} |
| c) | \displaystyle \left\{\eqalign{
x&=\displaystyle \frac{\pi}{20}+\displaystyle \frac{n\pi}{2}\cr x&=-\displaystyle \frac{\pi}{30}+\displaystyle \frac{n\pi}{3} }\right. |
