Problem 2.1: Define the arithmetic sequence a_n = 4n - 3 recursively. [Solution]

Problem 2.2: Define the arithmetic sequence a₁ = 6; a_n+1 = a_n - 2 explicitly. [Solution]

Problem 2.3: What is the sum of the first six terms of the sequence a_n = 2n + 6? [Solution]

Problem 2.4: What is the sum of the first 45 terms in the arithmetic sequence a₁ = 3; a_n+1 = a_n + 5? [Solution]