differential equation of a function determined by own increment at x-A

fogoetha

New member
Joined
Jun 10, 2021
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2
Hi everyone,
I posted below question on mathforums.com half a year ago, but never got any reponse. So I hope someone can help me out here:

2021-06-10 11_50_59-differential equation of a function determined by own increment at x-A _ M...jpg
kind regards
Frederik
 

nasi112

Full Member
Joined
Aug 23, 2020
Messages
425
You had a beautiful differential equation in the first part.

Do you mean this?

\(\displaystyle \frac{dy}{dx} = \frac{(H - By)}{A}\)

In the second part. I don't understand your differential equation.

Do you mean this?

\(\displaystyle \frac{dy}{dx} = \frac{H - By + B \ dy}{A}\)

I am sorry, but this is not a correct differential equation!
 

fogoetha

New member
Joined
Jun 10, 2021
Messages
2
You had a beautiful differential equation in the first part.

Do you mean this?

\(\displaystyle \frac{dy}{dx} = \frac{(H - By)}{A}\)

In the second part. I don't understand your differential equation.

Do you mean this?

\(\displaystyle \frac{dy}{dx} = \frac{H - By + B \ dy}{A}\)

I am sorry, but this is not a correct differential equation!
Dear @nasi112
Yes, I indicated that the formulation was inadequate.
but you also mean that the equation proposed by you is not even a valid formulation? This can be easily rewritten to contain only one 'dy', so I don't see the problem.
The real problem is that the additional dy should not refer to 'x' but to 'x-A'. I don't know how to incorporate this.
 

Subhotosh Khan

Super Moderator
Staff member
Joined
Jun 18, 2007
Messages
24,691
Hi everyone,
I posted below question on mathforums.com half a year ago, but never got any reponse. So I hope someone can help me out here:

View attachment 27722
kind regards
Frederik
What is the context of the problem? In other words, how did this problem arise - how was it formulated?
 

nasi112

Full Member
Joined
Aug 23, 2020
Messages
425
Dear @nasi112
Yes, I indicated that the formulation was inadequate.
but you also mean that the equation proposed by you is not even a valid formulation? This can be easily rewritten to contain only one 'dy', so I don't see the problem.
The real problem is that the additional dy should not refer to 'x' but to 'x-A'. I don't know how to incorporate this.
Show me how will you do it.
 

Subhotosh Khan

Super Moderator
Staff member
Joined
Jun 18, 2007
Messages
24,691
Dear @nasi112
Yes, I indicated that the formulation was inadequate.
but you also mean that the equation proposed by you is not even a valid formulation? This can be easily rewritten to contain only one 'dy', so I don't see the problem.
The real problem is that the additional dy should not refer to 'x' but to 'x-A'. I don't know how to incorporate this.
What is the context of the problem? In other words, how did this problem arise - how was it formulated?
Please answer the question/s posed above.
 
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