Understanding the Power Set of a Set X: Proving Its Existence | Homework Help

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Homework Statement



Let X be a set. Then the set

{Y:Y is a subset of X}

prove this is a set.Where do i start?

Really unsure, i know that i have to use the power set?

I have written down;

{0,1}^X
 
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What techniques have you learned so far? And what level of math is this for?
 
undergraduate analysis.
I know how to prove basic things, like umm.
If f and g are both injective then so is g composed with f etc.
i want to say that it is a collection of unordered objects and is therefore a set. (Waste of words, i know)

It just seems WAY to abstract, the fact that {Y: Y is a subset of X} is a set of subsets of a set, surely proves that it is in fact a set! :(.
 
What formal definition of "set" are you told to use?
 
there is no formal definition, there is an informal definition that says that:

We define a set A to be any unordered collection of objects.
 
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...
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