Final answer:
The subject of this question is Mathematics, specifically recursive and explicit sequences. It explains how Tania creates a chain letter and sends it to four friends, and each day the number of chain letters increases exponentially.
Step-by-step explanation:
The subject of this question is Mathematics, specifically the concept of recursive and explicit sequences. In this case, Tania creates a chain letter and sends it to four friends. Each day, each friend is then instructed to send it to four more friends. This creates a recursive sequence where the number of chain letters increases exponentially.
Alternatively, we can also represent this situation using an explicit formula. Let's say the initial number of chain letters Tania sends is 'a'. Then, on each day, the number of chain letters sent can be represented as 4 multiplied by the number of chain letters from the previous day (4^n).
By using either the recursive or explicit approach, we can understand and calculate the number of chain letters being sent each day.
The subject of this question is a mathematical sequence that illustrates an example of exponential growth. Tania creates a chain letter and sends it to four friends. Each day, every person who has received the letter is instructed to send it to four more friends. This results in the number of people who receive the letter increasing exponentially.
Recursive Formula:
The recursive formula for this sequence would be as follows:
An = 4 * An-1,
where An represents the number of chain letters on day n, and A1 = 4 (since Tania sends the letter to four friends on the first day).
Explicit Formula:
The explicit formula for this sequence is:
An = 4n,
where n is the number of days since Tania sent out the original letter