表达式4: "s" left parenthesis, "x" , right parenthesis equals "s" Subscript, 1 , Baseline left parenthesis, "x" , right parenthesissx=s1x
4
表达式5: "s" Subscript, 1 , Baseline left parenthesis, "x" , right parenthesis equals StartFraction, sin left parenthesis, pi times "x" , right parenthesis Over pi times "x" , EndFractions1x=sinπ·xπ·x
5
表达式6: "s" Subscript, 2 , Baseline left parenthesis, "x" , right parenthesis equals StartFraction, sin left parenthesis, pi times 2 "x" , right parenthesis Over pi times 2 "x" , EndFractions2x=sinπ·2xπ·2x
6
表达式7: "s" Subscript, 4 , Baseline left parenthesis, "x" , right parenthesis equals StartFraction, sin left parenthesis, pi times 4 "x" , right parenthesis Over pi times 4 "x" , EndFractions4x=sinπ·4xπ·4x