It is very handy to plot maths equations using the SAGE maths open source software.

For example, to plot a straight line:

> plot(3*x + 4, (x,0,5))

To plot a function, showing its asymptotes (requires us to set detect_poles=show):

> f = (5*x+2)/(2*x+3)

> plot(f, (x,-7,7), detect_poles='show').show(ymin=-50, ymax=50)

To plot a function, filling in the area between the function and its asymptote:

> plot(f, -7,7, fill = {0: [1]}, fillcolor='#ccc').show(ymin=-50, ymax=50)

To plot a trigonometric function:

> plot(tan(x), (x,-20,20), detect_poles='show').show(ymin=-10, ymax=10)

Plotting two functions on top of each other:

> plot(cos(x), (x,-3*pi,3*pi), color='blue') + plot(sin(x), (x,-2*pi,2*pi), color='red')

We can also plot parametric equations, for example, if x = t - sin(t), and y = 1 - cos(t), which is a cycloid curve:

> var('t')

> parametric_plot((t-sin(t),1-cos(t)),(t,0,30),rgbcolor=hue(0.6))

## 1 comment:

how do you get sage to display inflection points on a graph?

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