E 1: Choose the number of intervals as n = 5. Visually compare the quality of the three numerical approximations. Use the right window with its zoomed scale for that purpose, too.
E 2: Change the number of intervals n and compare qualitatively how the three approximations approach the analytic solution.
E 3: Make notes of the relative mistakes of the three methods with increasing n and draw a graph of their dependences. Compare this graph with a straight line for Euler and with a second grade parabola for Heun (with Runge−Kutta the deviations will be too small to clearly recognize the graph as a fourth grade parabola).
E 4: Open the file from the EJS console and study the code at page Initialization. Use other derivatives to solve different differential equations (for the exponential the derivative was simply y). The correct places are marked in red.