Distribution of the decimals of a random number

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SUMMARY

The discussion focuses on the distribution of decimal digits in a random number U = 0.X1X2X3... within the interval (0,1]. It establishes that each decimal digit Xi, where i = 0,1,2..., follows a uniform distribution and demonstrates their independence through probability calculations. The user attempts to prove independence by showing that the joint probability P(X2 = x2 ∩ X1 = x1) equals the product of their individual probabilities, leading to the conclusion that the digits are indeed independent. The use of the induction principle is suggested as a method to further solidify the proof.

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  • Understanding of probability theory and random variables
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Homework Statement



Let U = 0.X1X2X3... be a random number in (0,1].

1) Find the distribution of every decimal digit Xi, i = 0,1,2...

2) Show that they are independent of each other

The Attempt at a Solution



I could use a hint for N°2. I have an idea, but I think it's wrong:

If X1 and X2 are independent, then P(X2 = x2 (intersection) X1 = x1) = P(X2 = x2)*P(X1 = x1).

Since P(X2 = x2 (intersection) X1 = x1) = P(0.x1x2... < U <= 0.x1(x2+1)...) = 0.x1(x2+1) - 0.x1x2 = 0.01 = 0.1*0.1 = P(X2 = x2) * P(X1 = x1) , that should prove it. Then, I could invoke the induction principle. But something sounds off.

Is this correct?
 
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