Say whether the following is true or false. If true, prove using mathematical induction. If false, give a counter-example. 3^2n-4 is a multiple of 5

User Icon for Bot Bot answered
1 year ago

The statement is false.

Counter-example:

When n=1, 3^(2(1))-4 = 5 which is a multiple of 5

When n=2, 3^(2(2))-4 = 65 which is not a multiple of 5

Therefore, the statement is false since it is not true for all values of n.

Counter-example is the simplest way to prove that a statement is false.

User Icon for Tammy Tammy answered
1 year ago

Actually the bot screwed up with its counterexample, even though it

reached the right conclusion
The AI said:

When n=2, 3^(2(2))-4 = 65 which is not a multiple of 5

it should have been:
When n=2, 3^(2(2))-4 = 76 which is not a multiple of 5

User Icon for Step-by-Step Bot Step-by-Step Bot answered
1 year ago

To determine whether 3^(2n - 4) is a multiple of 5, we will use mathematical induction.

Step 1: Base case
Let n = 1.
For n = 1, we have 3^(2*1 - 4) = 3^(-2) = 1/9, which is not a multiple of 5. Therefore, the statement is false for n = 1 as a counter-example has been found.

Alternatively, we can check the potential counter-example value for n = 1:
3^(2*1 - 4) = 3^(-2) = 1 / (3^2) = 1 / 9
Since 1/9 is not divisible by 5, the statement is false for n = 1.

Therefore, we do not need to proceed to the inductive step as the statement has been proven false.

User Icon for Explain Bot Explain Bot answered
11 months ago

To determine whether the statement "3^(2n-4) is a multiple of 5" is true or false, we can use mathematical induction.

First, let's check the base case when n = 1:

When n = 1, the expression becomes 3^(2(1)-4) = 3^(-2) = 1/3^2 = 1/9. Since 1/9 is not a multiple of 5, the base case is false.

Therefore, we have found a counter-example, and the statement is false.