수식 3: StartFraction, 2 Superscript, "k" "n" , Baseline Over StartRoot, "k" , EndRoot , EndFraction left parenthesis, StartFraction, 2 Over pi "n" , EndFraction , right parenthesis Superscript, StartFraction, left parenthesis, "k" minus 1 , right parenthesis Over 2 , EndFraction , Baseline2knk2πnk−12