Expression 4: "s" Subscript, 1 , Baseline equals 1 half cosine left parenthesis, 2 pi "f" Subscript, "m" , Baseline "x" negative 2 pi "f" Subscript, "c" , Baseline "x" , right parenthesis Has graph. To audio trace, press ALT+T.s1=12cos2πfmx−2πfcx
4
Expression 5: "s" Subscript, 2 , Baseline equals negative 1 half cosine left parenthesis, 2 pi "f" Subscript, "m" , Baseline "x" positive 2 pi "f" Subscript, "c" , Baseline "x" , right parenthesis Has graph. To audio trace, press ALT+T.s2=−12cos2πfmx+2πfcx
5
Expression 6: "s" Subscript, 1 , Baseline plus "s" Subscript, 2 , Baseline Has graph. To audio trace, press ALT+T.s1+s2