Graph of a Quadratic

darcybundy shared this question 1 month ago
Answered

https://www.geogebra.org/m/y83ktgmm

My app has one bug. When I move the vertex of the quadratic y = a(x-p)^2+q up and down it changes the value of 'a'. I would like to be able to move my graph around without changing the value of 'a' while still retaining the possibility of changing the value of 'a'.

Comments (7)

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I think that your a depends of Vertex,so they changes together.I made same changes on your file,but I forgot to make copy of your file.I will delite it after few days,don`t worry. https://www.geogebra.org/m/qvppfntb

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Yes, but I'd like to be able to adjust the value of the vertical expansion 'a' without the slider

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your function environment

M = (2, -4)

a = (6, 0)

k=(-y(M) + y(a)) / (x(M)² - 2x(M) x(a) + x(a)²)

f(x)= k (x -x(M))² + y(M)

perhaps do you mean anything like that?

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This is a beautiful formula and allows me to set a vertex and set another point on the graph and I will be saving a copy of this absolutely.

But it doesn't solve the problem I was having.

Essentially, if I move the point B I would like the vertex to stay where it is. But if I move the vertex I would like B to move with the vertex.

https://www.geogebra.org/m/crbj9wza

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Hm,


this makes scripting necessary...

you can't make B dependent on vertex and move B with mouse (in this case B must be a free variable)

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I think I found a work around. I added a vector that can be moved around and it seems to do the job pretty well.

https://www.geogebra.org/m/j96cxjra

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I made a try

https://www.geogebra.org/m/akqxdnbk

You have to click (set Point Magenta) first and then drag with mouse

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