00:01
So given these different equations, we first want to write k as a function of r.
00:05
And to do this, we are going to equate the two equations that have k and r.
00:10
So we'll have y0 e to the kt.
00:16
That's going to be equal to y not times 1 plus r to the t.
00:30
We can cancel the y not from both sides by dividing.
00:34
And since we are solving, in this case, we're solving for k.
00:41
So we're going to take the natural log of both sides.
00:58
I'll take the natural log of both sides.
01:02
And that will get rid of this right here.
01:04
So we're less with kt equals this whole thing.
01:09
And then we can divide by t on both sides.
01:19
We'll take this whole thing and divide by t.
01:22
So we're left with this whole thing divided by t.
01:29
And then keep in mind when we have this t in the exponent with logs, that would be the same thing as having a t out in front multiplying.
01:37
So what we can do here is this t will cancel with the other t.
01:42
So we're told that k equals the natural log of 1 plus r.
01:46
So that is putting k in terms of r.
01:50
Relating those equations together.
01:54
Then for our next one, we want to get r in terms of r as a function of t2.
02:06
So to put r as a function of t2, we're going to choose the two equations that incorporate that...