00:01
In this problem we are given a first order vector initial value problem with the solution containing some constants to be determined and the task is to actually determine these constants.
00:15
So the differential equation is x prime equal to minus 6, minus 3 minus 6 times x plus 0, exponential, exponential, 60 with the initial condition 0.
00:37
So the solution is of the form x of t equal to c times exponential alpha t comma minus cosine beta t.
00:52
Okay, so we are going to start with the differential equation itself.
01:01
So we will take our expression we will compute its first derivative and put everything into this differential equation.
01:08
So the derivative of this guy is c for exponential alpha t times gamma minus cosine sine beta t plus c exponential alpha t there is beta coming from the vector, vector part of this expression, sine and cosine the second entry.
01:40
Now, if we compute the right -hand side, we obtain, okay, let's call this guy some a matrix, and that was called this vector b.
01:58
We have a times x plus b.
02:03
Equal to 3 c exponential alpha t minus two gamma plus two cosine plus sine beta t and the second component we have expansion minus 6 t plus 3 c exponential alpha t okay, that's a c.
02:32
And minus gamma plus cosine beta t minus 6c exponential for t.
02:48
So we will compare these expressions component by component...