There is another way.

You can generate lookup tables. Store these in arrays. Then a sin() function, for example, would simply look up the closest value of sin. There is almost no where you would need (and could practically use) more accurate values for trig functions. If I have time, I'll write some code to do that for sine. Check this site: http://nrg.chaosnet.org/uploads/resources for updates.

P.S: Cosine and tangent can be calculated for sine because cos(angle)=sin(angle+90 degrees) and tan=sin(angle)/sin(angle+90 degrees).