How Can Set Identities Help with Cartesian Product Homework?

  • Thread starter Thread starter ainster31
  • Start date Start date
  • Tags Tags
    Identity Set
ainster31
Messages
158
Reaction score
1

Homework Statement



9DXjR4I.png


Homework Equations



I have to use these set identities:

rD3CeXi.png


hW9GJqA.png


REAXX4U.png


The Attempt at a Solution



Pretty sure this is impossible because there's no identity for the Cartesian product.
 
Physics news on Phys.org
Just go at it the old fashion way.

Suppose (a, d) \in A X (B \cup C). Then a \in A. Also d \in B or d \in C. So (a,d) \in (A X B) or (a,d) \in (A X C).

Thus (a,d) \in (A X B) \cup (A X C).

Therefore A X (B \cup C) \subseteq (A X B) \cup (A X C).

Proving the subset goes the other way follows similarly.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top