How many functions are there that are equal to their own inverse function?

what is the best answer to

Question by Hello: How many functions are there that are equal to their own inverse function?
How many functions are there that are equal to their own inverse function?

I think only y=x, is there more?


Best answer:

Answer by Greg W
y = 1/x is also its own inverse.

Any function that has a graph symmetric to the line y = x is an inverse of itself.



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