№1
P₇=7!=5040
A³₈=8!/(8-3)!=336
C³₈=8!/5!3!=56
P₆/A⁵₇=6!2!/7!=2/7
№2
(n+1)!/(n-1)!=(n-1)!×n×(n+1)/(n-1)!=n²+n
(n-4)!/(n-2)!=(n-4)!/(n-4)!(n-3)(n-2)=1/(n-3)(n-2)=n²-5n+6
Copyright © 2024 SCHOLAR.TIPS - All rights reserved.
Answers & Comments
№1
P₇=7!=5040
A³₈=8!/(8-3)!=336
C³₈=8!/5!3!=56
P₆/A⁵₇=6!2!/7!=2/7
№2
(n+1)!/(n-1)!=(n-1)!×n×(n+1)/(n-1)!=n²+n
(n-4)!/(n-2)!=(n-4)!/(n-4)!(n-3)(n-2)=1/(n-3)(n-2)=n²-5n+6