00:01
All right, i'm going to solve this differential equation by taking the plus transform of both sides, and then i'm going to simplify it, and then i'm going to inverse the plus transform.
00:13
So i need l of y double prime, plus 2, l of y, plus, oh, y prime, plus 8, l of y, equals l of 0, which is a 0.
00:30
All right, so l of y prime, that's right here.
00:36
So s squared big y minus s times y of zero, which is minus 1, minus y prime of 0, which is 10, plus 2 times l of y prime prime, that's this one, 2sy minus y of 0, which is minus 8y prime, that's this one, 2sy minus y of 0, which is minus 1, plus 8y.
01:04
Equals 0.
01:07
So s squared plus 2 s plus 8 big y plus s minus 10 plus 1.
01:20
So minus 9 equals 0.
01:24
Did i get everybody? s squared 2s 8.
01:30
S minus 10 plus 1.
01:33
All right.
01:34
So s squared plus 2s plus 8.
01:38
Y equals minus s plus 9.
01:44
So y is minus s plus 9 over s squared plus 2s plus 8.
01:55
Okay, so now what are we going to do? b squared for...
02:22
I'm going to, i think, work on the bottom.
02:25
I think i'm going to complete the square there.
02:28
I'm going to add one and subtract.
02:31
One so i get s plus 1 squared plus 7 and so then on the top i need that minus s plus 9 to be in terms of s plus 1 so i can do this last thing to it so minus s plus 9 is minus okay i'm just going to make it s plus 1.
03:00
So what i did there was subtracted 1.
03:05
So i need to add one.
03:12
So this is the same thing as minus s plus 1 plus 10 over s plus 1 square plus 7 or minus s plus 1 over s plus 1 square plus 7 plus 10 s plus 1 square plus 7.
03:36
Okay, sorry.
03:38
Okay.
03:39
So so now i'm going to inverse transform...