Questions: The amount A of dollars accumulated after t years through an investment of A0 dollars at an interest rate of r, compounded continuously, can be determined from the function A=A0 e^rt. The doubling time of an investment is the time required for an investment to double in value. Find the doubling time (rounded to 3 decimal places) for an investment made at a. 8% interest compounded continuously.
years
Transcript text: The amount $A$ of dollars accumulated after $t$ years through an investment of $A_{0}$ dollars at an interest rate of $r$, compounded continuously, can be determined from the function $A=A_{0} e^{r t}$. The doubling time of an investment is the time required for an investment to double in value. Find the doubling time (rounded to 3 decimal places) for an investment made at
a. $8 \%$ interest compounded continuously. $\square$
years
Solution
Solution Steps
Step 1: Understand the Problem
We need to find the time \(T\) it takes for an initial investment to double when invested at an annual interest rate \(r\), compounded continuously.
Step 2: Apply the Formula for Continuous Compounding
The formula for continuous compounding is \(P = P_0e^{rt}\), where \(P\) is the future value, \(P_0\) is the initial investment, \(r\) is the annual interest rate, and \(t\) is the time in years.
Step 3: Set \(P = 2P_0\) to Find the Doubling Time
Since we want the investment to double, we set \(P = 2P_0\), which gives us \(2 = e^{rt}\).
Step 4: Solve for \(t\)
Taking the natural logarithm of both sides gives us \(\ln(2) = rt\). Solving for \(t\), we get \(T = \frac{\ln(2)}{r}\).
Step 5: Calculate the Doubling Time
Substituting \(r = 0.08\) into the formula, we get \(T = \frac{\ln(2)}{0.08} = 8.664\) years.
Final Answer:
The time it takes for the investment to double at an annual interest rate of 0.08 is approximately 8.664 years.