Math Is Fun Forum
Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °
You are not logged in.
- Topics: Active | Unanswered
Pages: 1
#1 2008-04-23 10:48:55
- chetah
- Member
- Registered: 2008-02-15
- Posts: 32
Discrete Maths
Determine the number of integer solutions of x1 + x2 + x3 = 6 where
a. xi > 0, 1 <= i <= 3
b. x1x2 >= 2 and x3 > 0
c. xi > 2, 1 <= i <= 3
the numbers and leter I are to be substrips.
Offline
#2 2008-04-23 13:14:30
- simron
- Real Member
- Registered: 2006-10-07
- Posts: 237
Re: Discrete Maths
So...
I conclude that I don't know anything about discrete maths.:P
Last edited by simron (2008-05-12 06:18:09)
Linux FTW
Offline
#3 2008-04-23 13:49:00
- John E. Franklin
- Member
- Registered: 2005-08-29
- Posts: 3,588
Re: Discrete Maths
part a.) (m-1)(m-2) / 2 ways, where m = 6, so (5)(4)/2 = 10 ways.
(This is just like my pie sharing post in this is cool with 3 people!!)
part b.) e.g. (-2)+(-2)+(10) e.g. (-5)+(-7)+(18)
infinite solutions if product of x1 and x2 go positive from 2 negatives.
part c.)
x1 x2 x3
no solutions because 3 + 3 + 3 > 6
igloo myrtilles fourmis
Offline
Pages: 1