- #1
ryanj123
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Homework Statement
There are two separate series I'm having trouble with, although they're related.
The scenario: Roll a fair die until a six comes up.
pmf = (5/6)^(x-1) * (1/6)
So first, show the sum from 1 to infinity of p(x) =1
Next, determine P(X=1,3,5,7,...) that it will appear on an odd roll.
Homework Equations
I'm trying to prove 1=sum (5/6)^(x-1) * (1/6)
and sum (5/6)^(2x-1) * (1/6) = ?
The Attempt at a Solution
For the first, I tried induction but got lost along the way.
The second, the back of the book states = 6/11 but getting there sends me back to computing the first series.