Answer 4.1:2
From Förberedande kurs i matematik 1
a) | \displaystyle \displaystyle \frac{\pi}{4}\textrm{ rad} | b) | \displaystyle \displaystyle \frac{3\pi}{4}\textrm{ rad} | c) | \displaystyle -\displaystyle \frac{7\pi}{20}\textrm{ rad} | d) | \displaystyle \displaystyle \frac{3\pi}{2}\textrm{ rad} |