Expression 3: "F" left parenthesis, "x" , right parenthesis equals "A" Subscript, 0 , Baseline plus Start sum from "k" equals 1 to "n" , end sum, "A" left bracket, "k" , right bracket sine left parenthesis, "k" "x" , right parenthesis plus Start sum from "k" equals 1 to "n" , end sum, "B" left bracket, "k" , right bracket cosine left parenthesis, "k" "x" , right parenthesis Has graph. To audio trace, press ALT+T.Fx=A0+n∑k=1Aksinkx+n∑k=1Bkcoskx