4.4 Compound Angle Formulas

Overall, we have to just remember the formulas which are in this chapter.
They are additional  Formula for sine and cosine:

sin (a+b) = sin a cos b + cos a sin b
sin (a-b) = sin a cos b -cos a sin b
cos (a+b) = cos a cos b - sin a sin b
cos (a-b) = cos a cos b + sin a sin b


sin(-b) = - sin b
cos (-b) = cos b


Additional information on how the formulas will be set so:
Let's watch some videos

*Be careful with the negative sign in additional formula for cosine.