SICP Exercise 3.78 solve-2nd

Exercise 3.78.  

Figure 3.35:  Signal-flow diagram for the solution to a second-order linear differential equation.
Consider the problem of designing a signal-processing system to study the homogeneous second-order linear differential equation

The output stream, modeling y, is generated by a network that contains a loop. This is because the value of d2y/dt2depends upon the values of y and dy/dt and both of these are determined by integrating d2y/dt2. The diagram we would like to encode is shown in figure 3.35. Write a procedure solve-2nd that takes as arguments the constants a, b, and dtand the initial values y0 and dy0 for y and dy/dt and generates the stream of successive values of y.

SOLUTION

 The code and tests are here.

 The plots are pasted below and also available here. 

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