Final answer:
To prove that for all natural numbers n, 3^n - 1 is an even number, we can use mathematical induction.
Step-by-step explanation:
To prove that for all natural numbers n, 3^n - 1 is an even number using mathematical induction, we'll follow these steps:
- Base case: Start by checking for n = 1. When n = 1, 3^n - 1 = 3^1 - 1 = 2, which is indeed an even number.
- Inductive hypothesis: Assume that for some k, 3^k - 1 is an even number.
- Inductive step: Show that if the statement holds for k, it also holds for k + 1. So, we need to prove that 3^(k + 1) - 1 is an even number using the assumption from the previous step.
- Conclusion: By the principle of mathematical induction, we can conclude that for all natural numbers n, 3^n - 1 is an even number.
Therefore, the statement is true.