can any one solve this ?

Question

moxtar 2020-6-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/550936-can-any-one-solve-this

评论： Rena Berman 2020-10-12

采纳的回答： Walter Roberson

6 个评论
显示 4更早的评论隐藏 4更早的评论

Rik 2020-6-19

Question removed by zheer sabir retrieved from Google cache:

Rena Berman 2020-10-12

(Answers Dev) Restored edit

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2020-6-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/550936-can-any-one-solve-this#answer_453685

编辑：Walter Roberson 2020-6-18

Q5) Proving that something cannot be solved "computationally" is hard work, typically worth a lot more than 5 points. Even Abel and Ruffini in their famous proof about the general solution of quintic polynomials, were satisfied with the very much more modest proof that no solution to those particular kinds of equations was possible with "algebraic numbers".

Providing an answer to this question requires Graduate courses in Computing Theory, Number Theory, Complex Analysis, and Differential Equations.

It is much easier, much easier, to give examples for which there is no known symbolic solution, rather than to prove that it cannot be solved computationally. (Heck, we don't even know whether

is rational, so there are big limits on what we know to be solvable computationally, https://math.stackexchange.com/questions/159350/why-is-it-hard-to-prove-whether-pie-is-an-irrational-number )

Q6) Unless the "set of data" mentioned first is infinite in extent, then the discrete set of known data is the same as the set of data.

Q7) Explicit numerical solution of what equation? The one from Q5? But the one from Q5 is not certain to involve multidimensional equations.

Note: multidimensional differential equations are not the same as multivariate differential equations.

The list of questions look to me like a joke exam. Check under your desk for a piano. http://www.ahajokes.com/impossible.html

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2020-6-19

Q6 and Q7 are not clear enough to be answered.

Q5 is potentially answerable. The shortcut to proving that something cannot be solved computationally is typically a proof by way of contradiction, along the lines of the proof that the real numbers are uncountable, or along the lines of Turing's Halting Problem. However, it is not at all clear that any differential equation related to such matters is solvable by an efficient numeric method.

moxtar 2020-6-19