##### August 05, 2012

### Snippets / Simple Sage Plots for Teaching Functions

JB

I'm teaching calculus to some homeschool students this year, and I wanted to have a bunch of function plots printed out to show them. Therefore, I turned to Sage, which I have never used. It is great! You have to know a few other math software pieces to really understand it, but it's not that bad. Someone needs to do a general "how to use sage", and some day I might.

Anyway, here's my quick function for plotting graphs for students that some of you might like.

In one of the evaluation boxes, type the following:

def simpleplot(f, range=(-5,5,-5,5)):

p = plot(f, (x, range[0], range[1]))

p += text("$" + latex(f) + "$", (0, range[2] - (range[3] - range[2]) * 0.1), fontsize=30, rgbcolor=(1,0,0))

p.axes_range(range[0], range[1], range[2], range[3])

show(p, figsize=12)

What this does is create a function called "simpleplot" which will do the following:

- Plot the given function on a default domain of -5, 5
- Typeset the function using LaTeX, and insert the function slightly below the graph (I calculated it at 10% of the graph size). It prints in red at 30 point size.

- Set the axes to be -5, 5, -5, 5 (I used uniform axes on all the functions so they can compare the differences between graphs easier)
- Draw the whole thing at 3x the normal size (figsize=12 - default is 4).

Now, I can just do:

simpleplot(1/x)

And it gives me my output!