Respuesta :
Answer:
8.66 years
Step-by-step explanation:
Given that:
Interest rate = 8%
Using the exponential growth function:
A = Ao * e^(rt)
Where A = final amount
Ao = Initial amount
r = growth rate
t = time
Here we are to calculate the time it takes an investment earning 8% interest to double;
rate (r) = 8% = 0.08
2A = A * e^(rt)
Divide both sides by A
2 = e^(rt)
2 = e^(0.08 * t)
2 = e^(0.08t)
In(2) = 0.08t
0.6931471 = 0.08t
Divide both sides by 0.08
0.6931471 / 0.08 = 0.08t / 0.08
8.6643397 = t
t = 8.66 years
Answer:
symbolically, the answer would be t= ln(2)/(.08)
Step-by-step explanation:
start by writing out your variables:
rate= .08
*dont forget the investment doubles too, thats where 2P is in the bottom equation
equation should look like:
[tex]2P=Pe^{.08t}[/tex]
then you solve, so divide P on the right and left:
[tex]\frac{2p}{p} = \frac{Pe^{.08t}}{p}[/tex]
now it looks like: [tex]2=e^{.08t}[/tex]
you can take the natural log (ln) of 2 to get the exponent by itself .08t
ln(2)=.08t
then divide .08 to get t by itself
[tex]\frac{ln(2)}{.08} =\frac{.08t}{.08}[/tex]
so symbolically, your equation should be:
[tex]t=\frac{ln(2)}{.08}[/tex]
to get t as your answer you can plug this equation into your calculator to get:
t=8.66 years so approximently 8 years