MATLAB int function problem while evaluating a symbolic definite integral

17 次查看（过去 30 天）
Emmanuel Florez Buitrago
评论： Emmanuel Florez Buitrago 2020-9-10
this is my code
syms x y z b
assume(b, 'positive')
h(x,y,z) = z /(x^2 + y^2 + z^2)^(3/2) ;
int(h, x , [0 b])
i want to get the result of this integral wich is:
(2 b z)/((y^2 + z^2) Sqrt[b^2 + y^2 + z^2])
but instead i get :
ans(y, z) =
piecewise(y^2 + z^2 == 1 & ((z^2)^(1/2) == z | z + (z^2)^(1/2) == 0), (b*z)/(b^2 + 1)^(1/2), y^2 + z^2 ~= 1 | (z^2)^(1/2) ~= z & z + (z^2)^(1/2) ~= 0, int(z/(x^2 + y^2 + z^2)^(3/2), x, 0, b))
what can i do to get the first answer ? is there something wrong in my code ?
  1 个评论
Walter Roberson
Walter Roberson 2020-9-10
Your proposed answer is not correct when there are certain relationships between the complex values x, y, z .
You have the assumption that b > 0, which implies that b is real, but the calculation needs to take into account that x, y, z are complex.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2020-9-10
simplify(ans, 'steps', 100)

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Numerical Integration and Differentiation 的更多信息

标签

产品


版本

R2020a

Community Treasure Hunt

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

Start Hunting!

Translated by