Friday

March 6, 2015

March 6, 2015

Posted by **Anonymous** on Saturday, August 28, 2010 at 7:02pm.

4.49 years

8.98 years

17.96 years

I'm not understanding this, I got 3.9 years when I tried to solve this.

- PreCalc -
**MathMate**, Saturday, August 28, 2010 at 7:32pmThe basic formula for compounding continuously is:

Lim (1+r/n)^(nt)

as n→∞

where t=number of years, and r is the annual interest rate.

which results in the formula:

A(t)=A(0)e^(rt)

For doubling,

A(t)/A(0)=2

Therefore:

e^(0.0772t) = 2

Take natural log on both sides to get:

0.0772t = ln(2)

Solve for t.

- PreCalc -
**Reiny**, Saturday, August 28, 2010 at 7:35pmcontinuous compounding formula is

amount = principal(e^(it)) , so

2 = 1(e^.0772t)

ln2 = ln (e^.0772t)

.0772 lne = ln2 , but ln e = 1

t = ln2/.0772 = 8.98

how did you get 3.9 ?

**Answer this Question**

**Related Questions**

compound interest - How do I solve these problems? Complete the table for a ...

math - If $3500 is invested at an interest rate of 6.25% per year, compounded ...

algebra - Hannah invests $3850 dollars at an annual rate of 6% compounded ...

Compound interest - Hello My teacher skipped over this and I have no clue how to...

Calculus Please help! - If 7000 dollars is invested in a bank account at an ...

Math - If 3000 dollars is invested in a bank account at an interest rate of 6 ...

algebra- Help fast - use the compound interest formula A=P(1+r/n)^nt and A=Pe^rt...

Calculus :) - If 8000 dollars is invested in a bank account at an interest rate ...

Financial Math - An investment of $2500 accumulates at 6% p.a compounded semi ...

Algebra - Greta invests $10,000 in an investment that pays 3% interest, ...