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In-Class Notes to Accompany Applied Combinatorics

Handout 9.2 Homogeneous Recurrence Equations

Example 9.3. Solving Advancement Operator Equations.

Solve the advancement operator equation
\begin{equation*} (A+4)f=0 \end{equation*}
with the initial condition \(f(0)=2\text{.}\)

Example 9.4. Applying Advancement Operator Polynomials.

Let \(c_{1}\) and \(c_{2}\) be constants and define \(f(n) = c_{1}3^{n} +c_{2}(-4)^{n}\text{.}\) Compute \((A+4)(A-3)f(n)\text{.}\)
Note: When solving
\begin{equation*} p(A)f(n)=g(n) \end{equation*}
weโ€™ll focus on \(p(0)\neq 0\text{.}\) Any factors of \(A\) in \(p(A)\) could be dealt with by shifting solutions.