
I appreciate it if you could tell me what type of function it's called, and how do I put this function on my TI-nspire calculator or on Wolfram Alpha.
Thank you.

I appreciate it if you could tell me what type of function it's called, and how do I put this function on my TI-nspire calculator or on Wolfram Alpha.
Thank you.
These are called Piecewise functions. They have different definitions, depending on the input domain.
Note. In that case though, it doesn't make much sense since it can simply be replaced by $$y=\sqrt{\vert x\vert}$$