Amber shared her photo with 3 people. They continued to share it, so the number of shares increases every day, as shown by the function:

[tex] f(x) = 3(4)^x [/tex]

Ben's Social Media Post:
Ben shared his post with 2 friends. Each of those friends shares with 3 more every day, so the number of shares triples every day.

Day Number of Shares:
- Day 0: 2

Carter's Social Media Post:
Carter shared his post with 10 friends, who each share with only 2 people each day.

Tasks:
1. Write an exponential function to represent the spread of Ben's social media post.
2. Write an exponential function to represent the spread of Carter's social media post.
3. Graph each function using at least three points for each curve. All graphs should be placed together on the same coordinate plane, so be sure to label each curve. You may graph your equation by hand on a piece of paper and scan your work, or you may use graphing technology.
4. Using the functions for each student, predict how many shares each student's post will receive on Day 3 and then on Day 10. Justify your answers.
5. If Amber decides to mail copies of her photo to the 45 residents of her grandmother's assisted living facility, the new function representing her photo shares is [tex] f(x) = 3(4)^x + 45 [/tex]. How does this graph compare with the original graph of Amber's photo shares?
6. Based on your results, which student's post travels the fastest? How is this shown in the equation form of the functions?
7. If you had to choose, would you prefer a post with fewer friends initially but more shares, like Amber, or more friends initially but fewer shares? Justify your answer with your calculations from previous questions.



Answer :

Sure, let's go through each part of the question step by step:

### 1. Exponential Function for Ben's Post
Ben initially shares his post with 2 friends. Each subsequent day, the number of shares triples. The exponential function representing this spread is:
[tex]\[ f(x) = 2(3)^x \][/tex]
This means that the initial number of shares (when [tex]\( x = 0 \)[/tex]) is 2, and it triples every day ([tex]\( 3^x \)[/tex]).

### 2. Exponential Function for Carter's Post
Carter shared his post with 10 friends, and each of those friends shares it with 2 people each day. The exponential growth function for Carter's share can be modeled as:
[tex]\[ f(x) = 10(2)^x \][/tex]
So, Carter's initial shares (when [tex]\( x = 0 \)[/tex]) is 10, and it doubles every day ([tex]\( 2^x \)[/tex]).

### 3. Graphing the Functions
To graph the functions, we'll evaluate each function at [tex]\( x = 0 \)[/tex], [tex]\( x = 1 \)[/tex], and [tex]\( x = 2 \)[/tex].

For Ben's shares:
- [tex]\( f(0) = 2 \)[/tex]
- [tex]\( f(1) = 2 \times 3 = 6 \)[/tex]
- [tex]\( f(2) = 2 \times 3^2 = 18 \)[/tex]

For Carter's shares:
- [tex]\( f(0) = 10 \)[/tex]
- [tex]\( f(1) = 10 \times 2 = 20 \)[/tex]
- [tex]\( f(2) = 10 \times 2^2 = 40 \)[/tex]

For Amber's shares (original function):
- [tex]\( f(0) = 3(4)^0 = 3 \)[/tex]
- [tex]\( f(1) = 3(4)^1 = 12 \)[/tex]
- [tex]\( f(2) = 3(4)^2 = 48 \)[/tex]

For Amber's shares (new function including mailing):
[tex]\[ f(x) = 3(4)^x + 45 \][/tex]
- [tex]\( f(0) = 3(4)^0 + 45 = 48 \)[/tex]
- [tex]\( f(1) = 3(4)^1 + 45 = 57 \)[/tex]
- [tex]\( f(2) = 3(4)^2 + 45 = 93 \)[/tex]

To visualize these functions together, you plot each of the points on a coordinate plane, labeling each curve distinctly.

### 4. Predicting Shares on Day 3 and Day 10
Using the functions, we can predict the number of shares:

For Ben:
- Day 3: [tex]\( f(3) = 2(3)^3 = 54 \)[/tex]
- Day 10: [tex]\( f(10) = 2(3)^{10} = 118098 \)[/tex]

For Carter:*
- Day 3: [tex]\( f(3) = 10(2)^3 = 80 \)[/tex]
- Day 10: [tex]\( f(10) = 10(2)^{10} = 10240 \)[/tex]

### 5. Comparing Amber's Original and New Graph
Amber's original function is [tex]\( 3(4)^x \)[/tex] and her new function, after mailing copies, is [tex]\( 3(4)^x + 45 \)[/tex].

- The original shares at Day 2: [tex]\( f(2) = 3(4)^2 = 48 \)[/tex]
- The new shares at Day 2: [tex]\( f(2) = 3(4)^2 + 45 = 93 \)[/tex]

The new graph will show a vertical shift upwards by 45 units, as evidenced by the addition of the 45 printing. The new graph at any point will consistently be 45 units higher than the original graph.

### 6. Fastest Traveling Post
By comparing the exponential growth rates of the posts:

- Ben: [tex]\( 2(3)^x \)[/tex] (base of 3)
- Carter: [tex]\( 10(2)^x \)[/tex] (base of 2)
- Amber: [tex]\( 3(4)^x \)[/tex] (base of 4)

Amber's post spreads the fastest because it has the highest base (4), showing a more rapid growth rate compared to the others.

### 7. Preference for Post Sharing
Choosing between fewer friends initially but more shares per friend (Amber) or more friends initially but fewer shares:

Given Amber's exponential growth with a base of 4, this results in a faster-growing spread. Despite waking fewer friends initially, the rate of increase (4 per day) outpaces the others over time.

Using our previous calculations:
- By Day 3, Amber already surpasses others with 48 shares compared to Carter's 80 and Ben's 54.
- By Day 10, Amber's shares would skyrocket past the others if calculated, proving exponential growth's substantial impact.

Hence, I would prefer Amber's strategy as it results in significantly higher shares quickly due to faster exponential growth.