A symbolic expression problem (different results in different version)

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Tamura Kentai 2020-4-22

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/519735-a-symbolic-expression-problem-different-results-in-different-version

编辑： Walter Roberson 2020-4-25

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

Hi, :

May I ask, I have a m-file, the content is as below, but it ran out different result in different versions of Matlab, they are 2013b & 2019a, or say, it's originally built in 2013b, but while migrating to 2019a on the other platform, it failed.

Can anyone know why, and how to solve it ? I found the issue was caused by the simple(), and the ezsym.m provided by the mathwork contributor.

The complete URL is here :

https://www.mathworks.com/matlabcentral/fileexchange/51195-ezsym-display-symbolic-expression-in-blank-plot

Thank you very much.

The code is here:

syms t a
fun = sin(a*t)
laplace(fun)
fun = sin(t)^2
laplace(fun)
fun = sin(t^2)
laplace(fun)
fun= 1/2 * ( exp(i*t^2) - exp(-i*t^2) )
A = laplace(fun)
% ezsym() was from Mathwork community contributor
% refer to: https://www.mathworks.com/matlabcentral/fileexchange/51195-ezsym-display-symbolic-expression-in-blank-plot
ezsym(A,26)
% simple() in Matlab2013b is ok, but failed at 2019a
simple(A)
syms s y(s)
y(s) = A
Num_Y = y(2*pi*1e4)
N_Sol = simple(Num_Y)
N_abs = double(abs(N_Sol))
N_angle = double(angle(N_Sol))