# Continuous Functions

1. Jun 14, 2013

### Justabeginner

1. The problem statement, all variables and given/known data
How many continuous functions f are there which satisfy the equation (f(x)^2) = x^2 for all x?

2. Relevant equations

3. The attempt at a solution
What method should I use to solve this? Is there a specific strategy involved besides plug and chug? Off the top of my head, I can only think of f(x)= x, but that's just one. Thank you.

2. Jun 14, 2013

### Office_Shredder

Staff Emeritus
If you take square roots:
$$\sqrt{ a^2} = |a|$$
Is always a true statement regardless of whether a is positive or negative. So for your equation you get |f(x)| = |x|. Try working from there

3. Jun 14, 2013

### Justabeginner

Thank you so much for that derivation!
For this absolute function, there would be two possible values: -x and x.
There would only be two functions possible then I think?
I thought it would be more complicated, and involve log functions, etc.