Proving Induction Inequality: 5^n+9 < 6^n for n>=2

In summary, the conversation is about an induction proof regarding the inequality 5^n + 9 < 6^n for all integers n>=2. The discussion centers around proving that statement P(k) is true and using that to show that statement P(k + 1) is also true. The conversation also touches on the concept of assuming a statement to be true in order to prove another statement.
  • #1
nastygoalie89
17
0

Homework Statement



5^n + 9 < 6^n for all integers n>=2.

Homework Equations




The Attempt at a Solution


Induction proof.

Base Case: 5^(2) + 9 < 6^(2)
34<36
P(k): 5^k + 9 < 6^k
P(k+1): 5^(k+1) + 9 < 6^(k+1)

how do i prove p(k) can equal p(k+1)?
 
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  • #2
nastygoalie89 said:

Homework Statement



5^n + 9 < 6^n for all integers n>=2.

Homework Equations




The Attempt at a Solution


Induction proof.

Base Case: 5^(2) + 9 < 6^(2)
34<36
P(k): 5^k + 9 < 6^k
P(k+1): 5^(k+1) + 9 < 6^(k+1)

how do i prove p(k) can equal p(k+1)?

You don't prove that P(k) = P(k+1). You assume that statement P(k) is true and use this fact to prove that statement P(k + 1) is also true.

From your induction hypothesis (statement P(k)) you are assuming that
5^k + 9 < 6^k

Work with 5^(k + 1) + 9 and see what you get.
 

FAQ: Proving Induction Inequality: 5^n+9 < 6^n for n>=2

What is the purpose of proving the inequality 5^n+9 < 6^n for n>=2?

The purpose of proving this inequality is to demonstrate the relationship between the powers of 5 and 6 for values of n greater than or equal to 2. This can help to understand the growth rate of these exponential functions and make predictions about their values for larger values of n.

What is the process for proving this inequality?

The process for proving this inequality is through mathematical induction. This involves showing that the inequality holds true for a base case (in this case, n=2), and then assuming it holds true for a general case (n=k) and using this assumption to prove that it also holds true for the next case (n=k+1). This process continues until the inequality is proven to hold true for all values of n greater than or equal to the base case.

Why is mathematical induction used to prove this inequality?

Mathematical induction is a commonly used proof technique in mathematics, particularly for proving statements that involve patterns or sequences. In this case, the inequality involves powers of numbers, which follow a certain pattern. Using mathematical induction allows for a systematic way to prove that the inequality holds true for all values of n, rather than having to test each individual case.

Can this inequality be proved using other methods?

Yes, it is possible to prove this inequality using other methods such as direct proof or contradiction. However, mathematical induction is the most commonly used method for proving inequalities involving patterns or sequences, as it provides a clear and organized approach.

What are the applications of proving this inequality?

Proving this inequality can have various applications in mathematics and other fields. It can be used to understand the growth rate of exponential functions, make predictions about their values, and solve related problems. It can also be used as a building block for proving other inequalities and mathematical statements.

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