Get expert advice and community support on IDNLearn.com. Our platform offers detailed and accurate responses from experts, helping you navigate any topic with confidence.

The population of butterflies increases from 2000 to 2800 over 7 years. Which function best models the population [tex]x[/tex] years from the first measurement?

A. [tex]f(x)=2000(1+0.4)^{\frac{1}{7} x}[/tex]
B. [tex]f(x)=2000\left(1+0.4^7\right)^x[/tex]
C. [tex]f(x)=2000\left(1+\frac{0.4}{7}\right)^x[/tex]
D. [tex]f(x)=2000\left(1+\frac{0.4}{7}\right)^{7x}[/tex]


Sagot :

To determine which function best models the population of butterflies [tex]\( x \)[/tex] years from the first measurement, we start by considering the given conditions:

- Initial population ([tex]\( P_{0} \)[/tex]): 2000 butterflies
- Final population ([tex]\( P_{f} \)[/tex]): 2800 butterflies
- Time span ([tex]\( t \)[/tex]): 7 years

We need to evaluate each function and see which one produces values that reasonably match the population growth from 2000 to 2800 over the 7-year period.

### Option A: [tex]\( f(x) = 2000 \left( 1 + 0.4 \right)^{\frac{x}{7}} \)[/tex]

For [tex]\( x = 1 \)[/tex]:
[tex]\[ f(1) = 2000 \left( 1 + 0.4 \right)^{\frac{1}{7}} \][/tex]
[tex]\[ f(1) \approx 2000 \times 1.049 \][/tex]
[tex]\[ f(1) \approx 2098.483 \][/tex]

### Option B: [tex]\( f(x) = 2000 \left( 1 + 0.4^7 \right)^x \)[/tex]

For [tex]\( x = 1 \)[/tex]:
[tex]\[ f(1) = 2000 \left( 1 + 0.4^7 \right)^1 \][/tex]
[tex]\[ f(1) \approx 2000 \times 1.00164 \][/tex]
[tex]\[ f(1) \approx 2003.2768 \][/tex]

### Option C: [tex]\( f(x) = 2000 \left( 1 + \frac{0.4}{7} \right)^x \)[/tex]

For [tex]\( x = 1 \)[/tex]:
[tex]\[ f(1) = 2000 \left( 1 + \frac{0.4}{7} \right)^1 \][/tex]
[tex]\[ f(1) \approx 2000 \times 1.05714 \][/tex]
[tex]\[ f(1) \approx 2114.286 \][/tex]

### Option D: [tex]\( f(x) = 2000 \left( 1 + \frac{0.4}{7} \right)^{7x} \)[/tex]

For [tex]\( x = 1 \)[/tex]:
[tex]\[ f(1) = 2000 \left( 1 + \frac{0.4}{7} \right)^7 \][/tex]
[tex]\[ f(1) \approx 2000 \times 1.475 \][/tex]
[tex]\[ f(1) \approx 2950.977 \][/tex]

### Conclusion:

Given that the butterfly population grows from 2000 to 2800 over 7 years, we are looking for a model that captures a significant increase over time. From our evaluations:

- Option A: [tex]\( \approx 2098.483 \)[/tex]
- Option B: [tex]\( \approx 2003.2768 \)[/tex]
- Option C: [tex]\( \approx 2114.286 \)[/tex]
- Option D: [tex]\( \approx 2950.977 \)[/tex]

Model [tex]\( D \)[/tex] estimates a final population of approximately 2950.977, which is the closest to the actual final population of 2800. Therefore, the best function that models the population is:

[tex]\[ f(x) = 2000 \left( 1 + \frac{0.4}{7} \right)^{7x} \][/tex]

Answer:

A.   [tex] f(x) = 2000(1 + 0.4)^{\frac{1}{7}x} [/tex]

Step-by-step explanation:

The number of years we know about is 7, so x = 7.

[tex] f(x) = 2000(1 + 0.4)^{\frac{1}{7}x} [/tex]

[tex] f(x) = 2000(1.4)^{\frac{1}{7} \times 7} [/tex]

[tex] f(x) = 2000(1.4)^{1} [/tex]

[tex] f(x) = 2000(1.4) [/tex]

[tex] f(x) = 2800 [/tex]

Answer: Choice A.