Geogebra
Try out Geogebra, here is
the home page, and here you find
the beta-versions
(opens in a new page). I have installed both version 4 and the
beta-version (to become version
5).
To start version 4, type: /chalmers/sw/unsup64/geogebra-4.2.47.0/geogebra
To start version 5, type: /chalmers/sw/unsup64/geogebra-4.9.225.0/geogebra-portable

Make yourself acquainted with Geogebra.

Save the following file (note it is not
a text file), lab.ggb,
and open it in Geogebra. Implement some
of the behavior in Matlab, so:
- One should be able to change the initial value, y0, using
the slider (but not by moving the point along the y-axis, since you
have used this technique already).
- You may assume that y0 lies in the interval [-1.5, 1.5] and the
time in [0, 20].
- Use ode45 to solve
the differential equation. You can assume that the differential
equation stays the same, i.e. y' = 0.1 y+ y^2.
- Switch off the warnings from ode45 (once your code is
working). The solution to the ode may have a singularity (depends on
the value of y0) and we do not want the see this warning all the time.
This is the way to switch of the warning:
warning('Off',
'MATLAB:ode45:IntegrationTolNotMet')