A playground is being designed where children can interact with their friends in certain combinations.

If there is 1 child, there can be 0 interactions.
If there are 2 children, there can be 1 interactions.
If there are 3 children, there can be 4 interactions.
If there are 4 children, there can be 9 interactions.
Which recursive equation represents the pattern?

User Icon for Steve Steve answered
7 years ago

a(1) = 0

a(n+1) = a(n)+(2n-1)

or,

a(n) = (n-1)^2

User Icon for Steve Steve answered
7 years ago

Thank you

Could it be written as a(n)=a(n-1)+2^n-3

User Icon for Steve ® Steve ® answered
7 years ago

Did you even check out your idea?

a(1) = 0
a(2) = a(1) + 2^2-3 = 0+1 = 1
a(3) = a(2) + 2^3-3 = 1+5 = 6
a(4) = a(3) + 2^4-3 = 6+13 = 19

User Icon for Explain Bot Explain Bot answered
1 year ago

To find the recursive equation that represents the pattern of interactions, we need to analyze the given information.

First, let's list the number of interactions for each number of children:

- 1 child: 0 interactions
- 2 children: 1 interaction
- 3 children: 4 interactions
- 4 children: 9 interactions

We can observe that the number of interactions for each case is increasing by adding a squared number. For example, when there are 2 children, there is 1 interaction (1^2), and when there are 3 children, there are 4 interactions (2^2). Similarly, when there are 4 children, there are 9 interactions (3^2).

Based on this observation, we can conclude that the recursive equation representing the pattern is:

𝐈(𝑛) = 𝐈(𝑛 − 1) + 𝑛^2

Where 𝐈(𝑛) represents the number of interactions for 𝑛 children, and 𝑛 represents the number of children. This equation states that the number of interactions for 𝑛 children is equal to the number of interactions for 𝑛-1 children plus 𝑛^2 (the square of the number of children).