Created
October 13, 2015 15:44
-
-
Save primaryobjects/63d485e68f7e50d73bfa to your computer and use it in GitHub Desktop.
n choose k
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| n choose k | |
| n! / k!(n - k)! | |
| How many pairs in: x,y,a,b,c,d,e,f | |
| 8C2 = 8! / 2! * (8 - 2)! = 40320 / (2 * 6!) = 40320 / (2 * 720) = 40320 / 1440 = 28 | |
| xy,xa,xb,xc,xd,xe,xf | |
| ya,yb,yc,yd,ye,yf | |
| ab,ac,ad,ae,af | |
| bc,bd,be,bf | |
| cd,ce,cf | |
| de,df | |
| ef | |
| https://www.google.com/webhp?sourceid=chrome-instant#q=8%20choose%202 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment