Incorrect integral calculation in MuPAD

2 次查看（过去 30 天）
Nishant Shankhwar
Nishant Shankhwar 2015-12-22
评论： Walter Roberson 2015-12-23
Integration of function x-1 wrt x using command int(x-1,x) in MuPAD gives answer as (x-1)^2/2 instead of x^2/2-x. Can anybody explain why?
Thanks in advance.
Regards Nishant

请先登录，再回答此问题。

回答（1 个）

Walter Roberson
Walter Roberson 2015-12-22
The difference between the two is 1/2 which is a constant and so falls into the usual "plus an arbitrary constant" category. If you diff((x-1)^2/2,x) you get x-1, so you cannot say that the result is incorrect.
  2 个评论
Nishant Shankhwar
Nishant Shankhwar 2015-12-23
Your argument is correct, but in sympy or maple same integral comes out to be x^2/2-x and diff(x^2/2-x,x) is x-1. Therefore x^2/2-x seems more convincing than (x-1)^2/2.
Walter Roberson
Walter Roberson 2015-12-23
x^2/2 - x might be more conventional but remember that the indefinite integral is really x^2/2 - x + a constant, so any result of the form x^2/2 - x + a particular constant + an implied constant is mathematically correct
It does look unusual, but the mathematics of it is sound.

请先登录，再进行评论。

类别

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

标签

Community Treasure Hunt

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

Start Hunting!

Translated by