A point such as ((a+b)^3,5a) is draggable but a point such as (sqrt(a+q),a/2) isn’t. I’m trying to figure out how I can format a point to ensure that it is draggable, but being as intuitive as possible. I would also like to find out how I could change a point to make it draggable. I couldn’t find an answer to either of these questions, so here I am.
Can you share a link to your graph? Normally I’d send calculator-specific questions to support.desmos.com, but I think this would still be useful for folks here building activities.
A point is only draggable if
- you define the coordinates explicitly and have Drag on
- you define each coordinate separately as a value (this is really the same as #1, but allows you to set the bounds and Step for each coordinate)
- you define your point using expressions and a single variable
I see both your examples are draggable, but only one of the variables can change at a time. You’ll see in this graph both points are draggable, but only the variables a and p are changed, while b and q are fixed.
It’s not letting me post a link, but here’s they key. Just put it at the end of the link to a blank graph: a2zaptpz9g; I’m trying to create an intuitive method for a rational graph that an also function as a reciprocal graph. Mainly this, but I’ve ran into this problem in the past. Thank you!
What behavior do you want with your “Help” point?
Only one variable per coordinate can change. So, if your expectation is that the graph change similar to what occurs with the green point, it won’t work this way. In “Help”, each coordinate uses a and q and only one variable can change, while the green point only uses q for the x-coordinate and a in the y-coordinate.
You can fix particular variables by making an expression or fraction. So, if you want p to be fixed for example, you can define it as p=1/1 and the slider will be removed.
You can also explicitly define the parts you don’t want to affect the movement. Like if you only wanted to adjust your point based on q, you can explicitly define the radical. Below has the original non-draggable point, and an edited point that will adjust based on q:
I’m trying to make it vary based on p, as I have a variable that varies on q and a.
Got it! So using the method for “fixing” a variable, I created variables a_0 = a/1 and q_0 = q/1. Using those in the point definition means only p is variable.
Would you send me the link to this graph? I tried doing something like that by having q_alt = q and a_alt = a, but it didn’t work. I just tried using q_0 and a_0 as you described, and it still didn’t work for me.
Click the bottom right corner where it says “edit graph on desmos”. Even without defining as a fraction, it works for me.
It works! Thank you so much!
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