00:01
For this problem, we're given that y prime is equal to y square times 1 plus 2x.
00:05
We're given initial condition that y of negative 1 is equal to 1, and our dx is equal to 0 .5.
00:11
So this question is really asking us to do two things.
00:13
First, we need to use euler's method to calculate the first three proxaminations using this initial value problem.
00:21
And then next, we want to calculate the exact solution and look at the accuracy of our approximations.
00:28
So first things that we need to recall is what exactly o 'yler's formula is.
00:34
So first thing to find our x -0, x -1, et cetera, our x -not comes from our initial value that we're given.
00:44
So our x -0 is just our negative 1, and 1 is our y -not.
00:50
To find the rest of the x -0s, or the x -ns, sorry, that is just going to come from a formula that xn is equal to xn minus 1 plus dx and then to find the rest of the y ends that is going to be y n minus 1 plus f of xn minus 1 y n minus 1 d x so first i'm just going to calculate our x's so x1 over it's we ready know x not is equal to negative 1 that's what we're given so next x1 is going to equal to negative 1 plus dx, which here is 0 .5.
01:40
So that's going to equal negative 0 .5.
01:47
And then x2 is going to equal x1 plus that plus 0 .5, which is just 0.
01:59
Okay.
02:00
Now we're going to actually find our approximation.
02:01
So first, y1, that's just going to equal to y0 plus f of x0, y, 0.
02:08
So it's just plugging x0 and y0 if x and y respectively so that's going to be y not squared times 1 plus 2 x not d x well again our y0 already given that's just 1 so it would be 1 plus 1 squared x not is negative 1 and d x is equal to 0 .5 and then when you put that in a calculator you should get that y1 is equal to 0 .5.
02:48
And i're going to continue similarly, just now adding one to these.
02:52
So now we're going to have y1 plus y1 squared times 1 plus 2x1 dx.
03:02
So our y1 we just found to be 0 .5.
03:09
Our x1, we found to be negative 0 .5.
03:14
And then our dx is still 0 .5.
03:18
And then when you multiply all of this out, you again actually get 0 .5...