Register to reply

Basic set theory question

by semidevil
Tags: basic, theory
Share this thread:
Oct3-04, 08:20 PM
P: 143
ok, find the intersection of i=1 to infinitie of A(i).

A(i) = [0, to 1/i].

I dont understand what it is asking. what do they mean to find the intersection of that?

and what if A(i) = [0, 1/n)
Phys.Org News Partner Science news on
Fungus deadly to AIDS patients found to grow on trees
Canola genome sequence reveals evolutionary 'love triangle'
Scientists uncover clues to role of magnetism in iron-based superconductors
Oct3-04, 10:01 PM
phoenixthoth's Avatar
P: 1,572
To use mathematicasque notation, Intersect[A(i), {i,1,oo}] is the set of all points in each A(i). There's only one point in all A(i)'s: 0. Therefore the intersection is {0}. Same with the second one. But if they made it (0,1/i) then it would be empty.
Oct3-04, 10:04 PM
P: 1,367
Do you mean:

[tex]\bigcap_{i=1}^{\infty} A(i)[/tex]

where A(i) = [0, 1/i]? Wouldn't the answer be {0}?

Register to reply

Related Discussions
Really, really basic question in set theory Set Theory, Logic, Probability, Statistics 11
Basic Set Theory Set Theory, Logic, Probability, Statistics 3
Basic Set Theory/Topology Set Theory, Logic, Probability, Statistics 6
Group theory question- very basic Introductory Physics Homework 1
Basic Graph Theory Question General Math 6