problem with calculation limit

14 次查看（过去 30 天）
saeed taheri
saeed taheri 2015-3-25
编辑： Roger Stafford 2015-3-25
Hi, I have recently used matlab to calculate the limit of the following function when E goes to minus infinity:
-E*(log(1/(exp(3*E) + 1))/(exp(3*E) + 1) - log(1/(exp(3*E + 3*a) + 1))/(exp(3*E + 3*a) + 1))
But Matlab returns:
limit(-E*(log(1/(exp(3*E) + 1))/(exp(3*E) + 1) - log(1/(exp(3*E + 3*a) + 1))/(exp(3*E + 3*a) + 1)), E == -Inf)
Does anybody knows what is going on? Am I doing something wrong?

请先登录，再回答此问题。

回答（1 个）

Roger Stafford
Roger Stafford 2015-3-25
编辑：Roger Stafford 2015-3-25
I would think the limit is zero by L'Hospital's rule, but it is possible that matlab's 'limit' function either doesn't know how to determine that or else it objects to the presence of the unknown variable 'a'. Try giving 'a' a specific value and see how it performs.

类别

在 Help Center 和 File Exchange 中查找有关 Programming 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