To apply this theorem, evaluate the function r left parenthesis theta right parenthesis equals theta plus sine squared left parenthesis StartFraction theta Over 3 EndFraction right parenthesis minus 8 at each endpoint of the interval left bracket negative 3 pi comma 3 pi right bracket. r left parenthesis negative 3 pi right parenthesisequals negative 3 pi minus 8 (Type an exact answer, using pi as needed.) Part 7 r left parenthesis 3 pi right parenthesisequals