Recursion depth of 1024 exceeded during evaluation of a complex substitution

Question

I am trying to do the following :

How do I obtain an expression for $\epsilon$

Why don't you trivially cut-and-paste the definition of σ from the first equation into the second and be done? Your syntax is all wrong too: Simplify[ ]. And there is no reason your Simplify call "knows" the first definition you've given. — David G. Stork, Feb 06 '18 at 23:20
Even after doing that I am not getting a simplified expression. — Indeterminate, Feb 06 '18 at 23:24
You could consider one of the options presented in this answer — Carl Woll, Feb 06 '18 at 23:47

score 3 · Answer 1 · edited Oct 21 '18 at 10:35

3

Using Format

Format[σ0] = Subscript["σ", 0];
Format[ϵ0] = Subscript["ϵ", 0];

σ = σ0/(1 - I ω τ);

ϵ = ϵ0 (1 + I σ/(ω ϵ0));

Simplify@ϵ

edited Oct 21 '18 at 10:35

Vinicius ACP

103
3

answered Feb 07 '18 at 00:42

Bob Hanlon

157,611
7
77
198

score 2 · Answer 2 · edited Feb 07 '18 at 07:34

2

Simply, subscripts don't work like that in Mathematica. When you define $\epsilon=\epsilon_\theta$, the $\epsilon$ on the right hand side is then substituted with the definition, because $\epsilon_\theta$ is not actually treated as its own variable.

σ = σθ (1 - I ω τ);
ϵ = ϵθ (1 + 
    I σ/(ω ϵθ));
Simplify[ϵ]

ϵθ + σθ (τ + I/ω)

Please also note that Simplify ϵ is literally interpreted as Simplify times ϵ, and will not result in any simplification. The square brackets are necessary for Simplify to have any effect.

Please also note that as written in your screenshot, the imaginary unit I will not be evaluated, as it is part of a variable name. To multiply I by something, make sure there is a (space) or * (asterisk) between them.

edited Feb 07 '18 at 07:34

Kuba

136,707
13
279
740

answered Feb 06 '18 at 23:23

eyorble

9,383
1
23
37

But I want the Sigma from equation 1 to be substituted into equation 2. – Indeterminate Feb 06 '18 at 23:27
1

Then put a space between the imaginary unit and the sigma, otherwise it's one variable. Will edit that in momentarily. – eyorble Feb 06 '18 at 23:29

Recursion depth of 1024 exceeded during evaluation of a complex substitution

2 Answers2