Difference between Matlab and Wolfram Alpha

62 次查看（过去 30 天）
Niklas Kurz
Niklas Kurz 2020-7-31
编辑： Niklas Kurz 2020-7-31
These problems might occure frequently due to the varied syntax. This time it's about:
solve(x^2-8*x+15<=1)
what gives (according to Matlab): pi and 4. That's wrong or not what I ask for. In contrast Wolfram Alpha gives after typing in the same piece of code the correct solution (in my point of view.) Why is that?

请先登录，再回答此问题。

采纳的回答

Jesús Zambrano
Jesús Zambrano 2020-7-31
Hi Niklas,
You need to set 'ReturnConditions' to true to return any parameters in the solution and conditions on the solution. Therefore,
S = solve(x^2-(8*x)+15<=1, 'ReturnConditions',true);
S.conditions,
ans =
x <= 2^(1/2) + 4 & 4 - 2^(1/2) <= x
in(y, 'real')
which is the solution interval: 2.5858 <= x <= 5.4142

更多回答（1 个）

Cam Salzberger
Cam Salzberger 2020-7-31
Hey Niklas,
Technically, both pi and 4 are "correct" results, as if you plug them in, they will fulfill the condition. I think what you are looking for is using the solution = solve(___, "ReturnConditions", true) syntax, as suggested by the solving inequalities example in the documentation.
Also, it would generally be helpful to post what you got from Wolfram as well, so we know what you're expecting.
-Cam
  1 个评论
Niklas Kurz
Niklas Kurz 2020-7-31
编辑：Niklas Kurz 2020-7-31
Thank you, guys
x <= 2^(1/2) + 4 & 4 - 2^(1/2) <= x
is what I'm looking for.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Animation 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by