how to find out any digit of any irrational number? We know that irrational number has not periodic digits of finite number as rational number.
All this means that we can find out which digit exist in any position of rational number.
But what about non-rational or irrational numbers?
For example:
How to find out which digit exists in Fortieth position of $\sqrt[2]{2}$ which equals  1,414213.......
Is it possible to solve such kind of problem for any irrational number?

In general, no.
Suppose that for every irrational number $r$ there were an algorithm that takes a natural $n$ as input and returns the $n$-th digit of $r$.
The possible algorithms are countable, all the irrationals are not, hence it is not possible to have such algorithms for every irrational.
However, such algorithms do exist for the so-called computable number.
