# Write this Equation using Mathematica

1. Jun 29, 2009

### EngWiPy

Hello everyone,

I have the following equation, and I want to write it using mathematica:

where:

and:

Where $$\Psi$$ is the tricomi's confluent hypergeometric function, built-in Mathimatica as HypergeometricU[ , , ].
Can any one help me, please?
Best regards

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2. Jun 30, 2009

### Staff: Mentor

I don't understand. What exactly is the difficulty? It seems straightforward, especially since you already know HypergeometricU.

3. Jun 30, 2009

### EngWiPy

Than you DaleSpam for replying. Actually, I took this equation from a paper which plotted it. When I tried to so do, the program gave may little bit different results, so, I thought that I wrote the program incorrectly using Mathematica. But after I posted this thread, I solved the problem, which was a matter of signs and powers.

Sorry for that, and thanks again.

Regards

4. Aug 4, 2009

### Mike^now

how we can find the law of formation of sequence in mathimatica????????????? plzzz help.

5. Aug 4, 2009

### Staff: Mentor

Hi Mike^now, welcome to PF

What does "law of formation of sequence" mean?

6. Aug 9, 2009

### Mike^now

it is a general rule to write a sequence. like 1/2,1/4,1/8/1/16,1/32.... has a general rule (1/2^n. where n = number of term.

7. Aug 9, 2009

### Staff: Mentor

That is not possible to do in general. No matter how many terms you write out, unless you already know the rule, you cannot know the next term.

For example, with the sequence you gave the next number could be 1/32, or the sequence could be cyclic and the next number could be 1/2 again, or it could be a bitshift of a floating point number with 5 bits of precision so that the next term is 0, etc.

8. Aug 13, 2009

### Staff: Mentor

Hmm, apparently they have a function which tries anyway:
FindSequenceFunction

9. Aug 30, 2009

### Mike^now

This function does not provide general term of sequence ( 4/3,5/4,6/5,7/6.....)

By writting FindSequenceFunction[{1, 4/3, 5/4, 6/5, 7/6, 8/7, 9/8}, n] produce as it is. no result.

even i tried sequence starting from 0 as well as from 1 and still it does not produce any formula of genral term.

Last edited: Aug 30, 2009
10. Sep 1, 2009

### Staff: Mentor

Well, that does not surprise me. As I said, it is fundamentally an impossible question. It is pretty impressive that it ever works.