Math Is Fun Forum

CIV

Member

Registered: 2014-11-09

Posts: 74

Reflection of the square root function over the y-axis.

Square Root Function:

Reflection of the Square Root Function across the y-axis:

Now, I know the domain of a square root has to be equal to or greater than zero. So that's when imaginary numbers are used. Right? 

It makes sense but at he same time it doesn't because when I pump the reflected square root function into my graphing calculator and view the table of values, I'm a bit confused as to how these value are calculated. I know that:

And that:

So if I have something like:

Solving this leaves me with:

So, how do I get 2 from 2i? Among the table of values, one of the many coordinate pairs are (-4,2). How is the value 2 acquired from 2i? What am I missing here? Thanks in advance. Oh, I asked my teacher and he said to seek tutoring. Lovely right?

CIV

Member

Registered: 2014-11-09

Posts: 74

Re: Reflection of the square root function over the y-axis.

Oh I just found out what I was doing wrong. Sorry. No imaginary numbers. It's a simple as:

Sorry. I feel stupid.

Olinguito

Member

Registered: 2014-08-12

Posts: 649

Re: Reflection of the square root function over the y-axis.

The domain of a function is important: it's the set of variables for which the function makes sense. In the case of the real-valued function

the domain is

. Always check the domain of a given function, or you might get confused.

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Bassaricyon neblina

CIV

Member

Registered: 2014-11-09

Posts: 74

Re: Reflection of the square root function over the y-axis.

Thanks you for the reply:) It's makes sense now. I have moments where I just can't seem to figure things out but when I do I kick myself but it's so simple. LOL.