We have

If θ = 15º then

so after some manipulation (left as an exercise),

These results may be combined with those from the previous section to find the sines and cosines of 3º and its multiples.

We have

If θ = 15º then

so after some manipulation (left as an exercise),

These results may be combined with those from the previous section to find the sines and cosines of 3º and its multiples.