#
Solve-2nd procedure
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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/dt²`

depends 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
`dt`

and the initial values
`y₀`

and
`dy₀`

for
`y`

and
`dy/dt`

and generates the stream of successive values of
`y`

.