Analyzing convergence of a simple difference equation

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I was playing with my calculator, had an arbitrary number on the screen, then pressed 1/x ,then sqrt, then 1/x, and so forth. I noticed it converged to 1.0 after a few back-and-forths. So, it occurred to me that I did not know how to prove that such procedure converges to one for an arbitrary number different from zero.

And when playing with different function pairs such as, $x^2$ and $\sqrt{x}$ (this time using a computer), I notice that I get other bounded patterns.

So, my question is regarding the convergence properties of a function of the following kind:

$$ y_{k+1}=f_{k\mod{2}}(y_k) $$

where both $f_0$ and $f_1$ are given functions, $y_0$ is a given real number, and $k=0, 1,\ldots,\infty$.

What can be said about $y_k$ as $k\to\infty$?

Pardon my lack of knowledge! I am sure someone has looked at this!

P.S. Some visuals for those so inclined.

note: migrated from mathoveflow at the request of @Anthony Quas

y0=0.5; y^2; sqrt(y)

y0=0.5; 1/y; sqrt(y)

y0=0.5; cos(y); sqrt(y)