表达式7: 20log left parenthesis, Start sum from "n" equals 0 to 30, end sum, StartFraction, "k" Superscript, left parenthesis, "n" plus floor left parenthesis, StartNestedFraction, "x" minus 1 NestedOver "l" , EndNestedFraction , right parenthesis , right parenthesis , Baseline Over "x" plus "n" times "l" , EndFraction , right parenthesis minus 20log left parenthesis, Start sum from "n" equals 0 to 30, end sum, StartFraction, "k" Superscript, left parenthesis, "n" , right parenthesis , Baseline Over 1 plus "n" times "l" , EndFraction , right parenthesis left brace, "x" greater than 1 , right brace20log30∑n=0kn+floorx−1lx+n·l−20log30∑n=0kn1+n·lx>1
7
表达式8: 20log left parenthesis, Start sum from "n" equals 0 to 0, end sum, StartFraction, "k" Superscript, left parenthesis, "n" plus floor left parenthesis, StartNestedFraction, "x" minus 1 NestedOver "l" , EndNestedFraction , right parenthesis , right parenthesis , Baseline Over "x" plus "n" times "l" , EndFraction , right parenthesis minus 20log left parenthesis, Start sum from "n" equals 0 to 0, end sum, StartFraction, "k" Superscript, left parenthesis, "n" , right parenthesis , Baseline Over 1 plus "n" times "l" , EndFraction , right parenthesis left brace, "x" greater than 1 , right brace20log0∑n=0kn+floorx−1lx+n·l−20log0∑n=0kn1+n·lx>1
