Expression 3: "L" Subscript, "n" , Baseline left parenthesis, "x" , right parenthesis equals Start sum from "k" equals 0 to "n" , end sum, StartFraction, "n" ! left parenthesis, negative 1 , right parenthesis Superscript, "k" , Baseline Over left parenthesis, "n" minus "k" , right parenthesis ! times left parenthesis, "k" ! , right parenthesis squared , EndFraction "x" Superscript, "k" , BaselineLnx=n∑k=0n!−1kn−k!·k!2xk
3
Expression 4: "L" Subscript, "n" , Baseline left parenthesis, "x" , right parenthesis times "e" Superscript, negative "x" , BaselineLnx·e−x