4. As shown in the required reading or videos let {an) and (bn) be convergent sequences such that lim an = L₁ and lim b₁ = L2. Prove, using 71-8 N. € type methods only, that the limit operator is linear and, distributes across sums such that lim an+lim bn = L₁ + L2 21 an 21-100

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Chapter2: Second-order Linear Odes
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### Problem 4: Limit of the Sum of Convergent Sequences

As shown in the required reading or videos, let \(\{a_n\}\) and \(\{b_n\}\) be convergent sequences such that:

\[
\lim_{n \to \infty} a_n = L_1 \quad \text{and} \quad \lim_{n \to \infty} b_n = L_2
\]

Prove, using \(N, \epsilon\) type methods only, that the limit operator is linear and distributes across sums, such that:

\[
\lim_{n \to \infty} a_n + \lim_{n \to \infty} b_n = L_1 + L_2
\]

### Detailed Explanation

To approach this problem, we'll use the formal definition of limits involving \(N\) and \(\epsilon\):

1. Since \(\{a_n\}\) converges to \(L_1\), for every \(\epsilon > 0\), there exists a positive integer \(N_1\) such that for all \(n \geq N_1\), \(|a_n - L_1| < \epsilon/2\).
2. Similarly, since \(\{b_n\}\) converges to \(L_2\), for every \(\epsilon > 0\), there exists a positive integer \(N_2\) such that for all \(n \geq N_2\), \(|b_n - L_2| < \epsilon/2\).

Given these definitions, our goal is to show that \(\lim_{n \to \infty} (a_n + b_n) = L_1 + L_2\).

#### Step-by-Step Proof:

1. **Combine the Inequalities:**
   We aim to combine the inequalities for \(|a_n - L_1|\) and \(|b_n - L_2|\). Since \(\epsilon\) is arbitrary, we choose \(\epsilon/2\) to ensure we can add the two sequences while controlling both within a total of \(\epsilon\).

2. **Find a Common \(N\):**
   Let \(N = \max(N_1, N_2)\). This selection ensures both inequalities \(|a_n - L_1| < \epsilon/2
Transcribed Image Text:### Problem 4: Limit of the Sum of Convergent Sequences As shown in the required reading or videos, let \(\{a_n\}\) and \(\{b_n\}\) be convergent sequences such that: \[ \lim_{n \to \infty} a_n = L_1 \quad \text{and} \quad \lim_{n \to \infty} b_n = L_2 \] Prove, using \(N, \epsilon\) type methods only, that the limit operator is linear and distributes across sums, such that: \[ \lim_{n \to \infty} a_n + \lim_{n \to \infty} b_n = L_1 + L_2 \] ### Detailed Explanation To approach this problem, we'll use the formal definition of limits involving \(N\) and \(\epsilon\): 1. Since \(\{a_n\}\) converges to \(L_1\), for every \(\epsilon > 0\), there exists a positive integer \(N_1\) such that for all \(n \geq N_1\), \(|a_n - L_1| < \epsilon/2\). 2. Similarly, since \(\{b_n\}\) converges to \(L_2\), for every \(\epsilon > 0\), there exists a positive integer \(N_2\) such that for all \(n \geq N_2\), \(|b_n - L_2| < \epsilon/2\). Given these definitions, our goal is to show that \(\lim_{n \to \infty} (a_n + b_n) = L_1 + L_2\). #### Step-by-Step Proof: 1. **Combine the Inequalities:** We aim to combine the inequalities for \(|a_n - L_1|\) and \(|b_n - L_2|\). Since \(\epsilon\) is arbitrary, we choose \(\epsilon/2\) to ensure we can add the two sequences while controlling both within a total of \(\epsilon\). 2. **Find a Common \(N\):** Let \(N = \max(N_1, N_2)\). This selection ensures both inequalities \(|a_n - L_1| < \epsilon/2
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