Hi guys, I need help with this simple question. I missed lectures about this, and I don't not clue how to do this. Could someone explain to me how to do this or do it for me so I try and figure out how these questions are done.

(b) Given the relation R such that R = {(m, n) ∈ R|m, n ∈ A, m2 − n > 2} when A
is the set {0, 1, 2, 3, 4}
(i) Express the relation R as a set of ordered pairs.

You are asked to find all ordered pairs (m,n) of elements of A such that m² - n > 2 :

It's clearly impossible when m = 0 or 1.

If m = 2, then 4 - n > 2 turns to n < 2 :
(2,0), (2,1)

If m = 3, then the condition on n is n < 7 :
(3,0), (3,1), (3,2), (3,3), (3,4)

If m = 4, then, just as before, every n in A satisfies the equation :
(4,0), (4,1), (4,2), (4,3), (4,4)

"Expressed as a set" :

R = { (2,0), (2,1), (3,0), (3,1), (3,2), (3,3), (3,4), (4,0), (4,1), (4,2), (4,3), (4,4) }

Thanks a lot for help, I got it now! I need help with another question =


This post was edited by Marcelpro on Dec 13 2016 12:15pm

Tried the Binomial theorem ?

https://en.wikipedia.org/wiki/Binomial_theorem

I have look at all of the examples online but I seem not get what they are doing. I got the answer pf 36, would that be right?

It will be 3^4 * binom(11,4)
which is :

81 * 11 * 10 * 9 * 8 / ( 4 * 3 * 2 )

81 * 11 * 10 * 3

26730