Range & PMF of Y for X ∼ Geometric(1/3)

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Homework Statement


Let X∼Geometric(1/3), and let Y=|X−5|. Find the range and PMF of Y.

Homework Equations


Px(k) = p(1-p)^(k-1) for x=1,2,3...

3. My attempt at a solution
I set up the PMF for Px

Px(k) = 1/3(2/3)^(k-1) for k = 1,2,3,...
However I don't know how to convert this to Y
 
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Jonobro said:

Homework Statement


Let X∼Geometric(1/3), and let Y=|X−5|. Find the range and PMF of Y.

Homework Equations


Px(k) = p(1-p)^(k-1) for x=1,2,3...

3. My attempt at a solution
I set up the PMF for Px

Px(k) = 1/3(2/3)^(k-1) for k = 1,2,3,...
However I don't know how to convert this to Y

Really? For what values of ##X## do you get ##Y = 0##? Which value (or values) of ##X## give you ##Y = 1##? Etc., etc.
 
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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