00:01
So in our question, we've been given that f of t is equal to e to the power 4 t plus 5.
00:13
So this implies that if you are supposed to find f of l of f of t, this will be l of a to the power of 40 plus 5.
00:28
So simplifying this, you're going to get l of e to the power 40 plus l of 5.
00:36
So from here we are going to get 1 over s minus 4 plus 5 times 1 over s.
00:48
So based on this answer, it implies that if you are given l of a to the power a t, you are going to get 1 over s minus a.
01:02
And if you are given l of 1, you will be equal to 1 times 1 over s.
01:10
Which is the same as 1 over s.
01:15
So continue with our simplification, you're going to get s plus 5 into bracket s minus 4.
01:23
Divided by s times s minus 4.
01:30
So we get s minus 20 over s squared minus 4 s.
01:39
So now the second option is true.
01:43
So going to the next one, saying it's giving that f of t is equal to 4 sign 3 t plus 90.
02:06
So applying the same rule, getting l of f of t will be equal to l of sine 3t plus 90.
02:26
So simplifying this, you're going to bring four outside.
02:32
Then you're going to get l over here.
02:50
So we get sign 3t plus 2 outside.
03:01
We have l plus 90.
03:11
So this implies that i'm going to get four times.
03:16
You have 3 divided by s squared plus 3 squared plus 2 times s over.
03:28
You have s squared plus nine squared so this is based on when you are given l of sign b t you will be equal to b over s squared plus b squared and when you are given l of course b t this is equal to s over s squared plus b b this is equal to so now continue with our simplification.
04:14
We are going to get 12 over s squared plus 9 plus 2s over s squared plus 81...