A person invests in an account with interest compounded continuously according to the formula

[tex]\[ A = f(t) = 11100 e^{0.022 t} \][/tex]

where [tex]\( A \)[/tex] is the amount in the account and [tex]\( t \)[/tex] is in years.

1. Find [tex]\( f(0) = \$ \square \)[/tex]

2. To the nearest cent, find the amount in the account after 9 years.
[tex]\[ \$ \square \][/tex]

3. To the nearest tenth of a year, determine how long it will take for the investment to grow to [tex]\( \$ 12400 \)[/tex].
[tex]\[ \square \text{ years} \][/tex]



Answer :

Sure, let's take this step-by-step:

1. Finding [tex]\( f(0) \)[/tex]:

Given the formula for the amount in the account:
[tex]\[ A = f(t) = 11100 e^{0.022 t} \][/tex]

To find [tex]\( f(0) \)[/tex], we substitute [tex]\( t = 0 \)[/tex]:
[tex]\[ f(0) = 11100 e^{0.022 \cdot 0} \][/tex]

Since [tex]\( e^0 = 1 \)[/tex]:
[tex]\[ f(0) = 11100 \times 1 = 11100 \][/tex]

So,
[tex]\[ f(0) = \$11100.00 \][/tex]

2. Finding the amount in the account after 9 years:

To find the amount after 9 years, substitute [tex]\( t = 9 \)[/tex] into the formula:
[tex]\[ A = 11100 e^{0.022 \cdot 9} \][/tex]

Using the given information:
[tex]\[ A \approx 13530.48 \][/tex]

Therefore, to the nearest cent, the amount in the account after 9 years is:
[tex]\[ \$13530.48 \][/tex]

3. Determining the time it will take for the investment to grow to \[tex]$12400: We need to find \( t \) when the amount \( A = 12400 \): \[ 12400 = 11100 e^{0.022 t} \] To isolate \( t \), we first divide both sides by 11100: \[ \frac{12400}{11100} = e^{0.022 t} \] \[ \frac{12400}{11100} \approx 1.117117 \] Take the natural logarithm (ln) of both sides: \[ \ln(1.117117) = 0.022 t \] Solve for \( t \): \[ t = \frac{\ln(1.117117)}{0.022} \] Using the given information: \[ t \approx 5.0 \] Therefore, it will take approximately: \[ 5.0 \] years for the investment to grow to \$[/tex]12400.