2. The function x = cos 6/ cos 7/ has mean frequency co =13/2 and half difference S =1/2. Thus, /131\/13 IN cos 6f cos It = cos t cos +-11,\22)\22)113=2 sin -t sm t.22 Plot the graph of x, and superimpose the "envelope" of the beats, which is the slow frequency oscillation y(t)=2 sin(1(2)t. Use different line styles or colors to differentiate the curves.