00:01
Hi, so first it is 1 .1.
00:05
Solve the differential equations i .e.
00:09
D square y of t divided by dt square plus 4y of t equals to 8t square minus 20t plus 8.
00:22
We will now find the complementary solution to the lhs part equals to 0.
00:31
We say that let y of t be e raise to lambda t d square by dt square of e raise to lambda t plus 4 e raise to lambda t equals to 0.
00:51
So that means lambda square e raise to lambda t plus 4 e raise to lambda t equals to 0.
01:01
So that means this implies that lambda is equal to plus minus 2i.
01:09
Y of t will be equal to c1 e raise to 2it plus c2 e raise to minus 2it and so we can say that y of t will be c1 of cos of 2t plus i sin of 2t plus c2 cos of 2t minus i sin of 2t.
01:46
So y of t will be c1 plus c2 cos of 2t plus i c1 minus c2 sin of 2t.
02:01
So now we will be finding the particular solution yp of t will be a1 plus a2t plus a3t square.
02:23
So first now we will find yp double dash and we get it as 2a cube yp dash it is a2 plus 2a cube t.
02:43
Further solving we get a1 as 1 a2 as minus 5 a3 as 2.
03:02
So y of t will be 2t square minus 5t plus c1 cos of 2t plus c2 sin of 2t plus 1.
03:18
So here we have second one y double dash of t plus y dash of t minus 2y of t equals to 3 cos of 2t.
03:28
Also the initial conditions given that is y of 0 is minus 1 y dash of 0 is 2.
03:34
We find the complementary solution to the left -hand side...