a. Calculate AA and AA . (Recall the definition of the rotation matrix on p. 98.) b. Use your answer to part a to derive the addition formulas for sine and cosine.

' Jl \ tir:+ \)nv \vc{ rvr\ ft'\cu { {,\',rVc,fL"-,cr >o Dnr,er'trr',) eW - L c / /,-'-t-'7 WN -[ '["O, o^ 1.,r,,t/\ i,1 , fLun { ,str)crtn>,jul .l'(v).u At ,-/,*,rn J ,j4.*,tf ts dut,or!gr,v...t Clilict\...