00:02
The formula for continuous compound interest is p times e to the rt.
00:13
We want to know if we have an initial investment, so a p of $900, and we want to double that, so we want a to be two times $900, $900.
00:43
It will double in six and a half years.
00:53
Okay, so we're going to use that information to get the interest rate.
00:58
So i'm starting with my principle of p, and then i'm going to end up with two times p, and that is going to take six and a half years.
01:10
So i'm going to put in 6 .5.
01:14
Divide both sides by 900, so i have two equals, e to the 6 .5r.
01:21
Take the log of both sides, natural log...