Inverse trigonmetric functions in ccs v3.3 dsp28335

I am not using iqmath. Earlier sin(),cos() also created problems (Prob was that my sensed variable frequencies were wrong if i include sin() or cos(), but that i temporarily solved by reducing my switching freq from 10 to 5khz.....)
Now the problem is in inverse trig functions as you can see in last line of code.

Some suggested to use LUT for sin and cos to save time in fetching sin and cos values.Please let me know whether that is a good solution. If so, how to go about doing it.

Thanks a lot.