I am new to this CL, get an idea but I do not know how to start. I have read some instructions but somehow still not get it. Can some one, pls help me.

The graph need to get input from the answer math box

I understand that when I have nothing, no one want to help.
I know that I have to use parseEquation differenceFunction simpleFunction, to graph the function from math box, but most example I read here, they all do with x as input and y as output. In my case, I want student write y = f(x) + 2 (where f(x) as input and y as output.

Can someone show me some light? Thank you in advance

Using f(x) isn’t as straightforward as one would like. I put together a similar transformation activity, but I borrowed from Mike Gleeson on this CL Forum for the nuts and bolts of animating the transformation using af\left(B\left(x-h\right)\right)+k

Hi Stein
Thank you very much for your guidance and help.
I now see that the graph can not get the input function from its own existing function, In its own, there is just a defined one as placeholder, then will be replaced by the outside via the math box input.
In the example you sent me, I see there are two math boxes, one is for parent function and one for children function, then both of them just pass into the graph.
This approach works but students in general could not come up with a parent function that really shows both vertical and horizontal stretch.

Following your advice, I searched the CL Forum and saw you work on function transformation. Very impressive. I love it, can I use it for my class?
Also, I would love to see if you can add the absolute transformation, f(x) → |f(x)| and f(|x|) then it will make a complete packet about transformation using notation.

You are more than welcome to use the desmos activity. I probably won’t get around to adding the absolute value transformations in the near future, but I think it is a great idea.
Stein

For what it’s worth, this is very far from beginner stuff. You’ve discovered an anomaly with Desmos Activity Builder and function representation for which it is very difficult to code solutions.

Don’t let that discourage you! The absolute value issue is far from trivial so keep on hacking.

Thank Stein and Mike for your time of coaching me. This is what I got Function Transformation • Activity Builder by Desmos
Most of it are the copying of your work. I still do not get all the coding syntax yet (I do not worry much of these, because different software vendor will use different syntax) but I understand the work flow now, what go into what and output what. I think this is more important. Once I know what should be done, then I can just do some research about its syntax.
I feel good of what I have and again, thank you for all of these.