How could we express the above integral in a similar form if the upper limit of the integral was some constant T rather than oo?

beefypy

beefypy

Answered question

2022-10-14

Try to deal with a problem, that might actually be related to Laplace transform. Here is brief overview. Let P ( t ) = p m t m + + p 1 t + p 0 . Then we know that,it is possible to express the following integral in the form.
0 e z t P ( t ) = a = 0 m p a a ! z a + 1 ,
where the equality comes from the property of Laplace transform.

Answer & Explanation

Jean Deleon

Jean Deleon

Beginner2022-10-15Added 14 answers

You can use the lower incomplete gamma function
(1) γ ( s , x ) = 0 x t s 1 e t   d t
In your case
(2) 0 T t k e z t   d t = z k 1 0 T ( z t ) k e z t   d ( z t ) = ( 1 ) z k 1 γ ( k + 1 , z T )
So that
(3) 0 T P ( t ) e z t   d t = k = 0 m p k 0 T t k e z t   d t = ( 2 ) k = 0 m p k γ ( k + 1 , z T ) z k + 1
If you take T you have γ ( k + 1 , z T ) Γ ( k + 1 ) = k ! which leads back to your last expression

Do you have a similar question?

Recalculate according to your conditions!

New Questions in Differential Equations

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?