Help with symbolic plotting

gibxam

Hello everyone,

I've been in university for about 3 years now and the tool I want more than anything is something that can make plots symbolically. What I mean is if for example i have the following function:

f[x]=ln[[itex]\frac{x}{β}[/itex]]

I want a plot that will know to plot a function that is just like the ln[x] except that when x=β the plot will go through the x-axis. Meaning the program if it exists will know to have the x-axis with a tick mark labeled β.

this would be super useful for me because up until this point I have been using mathematica and just make all my constants 1 and then change them around, which works fine but it would look so cool to have a qualitative graph that I could look at also. Does this exist anywhere? Also no big deal if it doesn't but then does anyone have any cool tips with Mathematica or some other software to make their plots quick and easy with?

thanks

max

Bill Simpson

It is difficult for me to think how this would be done in general.

Imagine you are that software for a moment and I tell you I want a plot of
y=a*x+b
or
y=a*x^2+b*x+c
or many more complicated functions
and I want you to give me back exactly the plot I am imagining.

How could you do that?

Yes I suppose that you can substitute 1 for all coefficients, if that makes the plot that you want. Then why not just substitute 1 for all the coefficients and plot it?

As a general estimate I expect that it will take about as much time and work to get the mathematics approximately right as it will take to get the graphics approximately right. And it will take between two and ten times longer to get each of those very close to what I want. If you are sort of tossing out the mathematics part and just looking at the graphics part then I wouldn't be surprised if you still have a substantial amount of time and work to get something that looks the way you want. Computer math software has just not yet implemented the "do what I want" button.

Number Nine

The second reason it would not work, extending what was written above, is that every new parameter adds another dimension to the model. Under your system, even a linear equation defines a three dimensional surface in four dimensional space.

chiro

Hey max.

If you are interested solely on how β affects your function, it would be better to just plot an output function as a function of β and x and then view it 3D and rotate, translate, and scale the function using a standard software package.