Questions about Mathematica's rule-based replacement functionality, including functions such as Rule (->), Replace, ReplaceAll (/.) and ReplaceRepeated (//.).

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6
votes
3answers
395 views

Replacement rule only matches part of expression

I have the result of a calculation (which is too long to mention here) and it gives ...
4
votes
1answer
189 views

Replace rule does not match

I have the following expression -3 I Ez Re[Ex] + 3 I Ex Re[Ez] And I wish to write this in the form ...
4
votes
1answer
325 views

Replace rule also matching complex numbers

I'm having the replace rule: rule = {-g_ x_^4 - 2 g_ x_^2 y_^2 - g_ y_^4 -> -g (x^2 + y^2)^2}; Now, ...
9
votes
3answers
1k views

Replace expressions with symbols

First of all: I'm new to Mathematica, so I would appreciate it if the answers are quite complete. I have the result of calculation that is expressed in $\sin$ and $\cos$. Now, all of these can be ...
12
votes
7answers
4k views

How do I replace a variable in a polynomial?

How do I substitue z^2->x in the following polynomial z^4+z^2+4? z^4+z^2+4 /. z^2->x ...
45
votes
3answers
1k views

Replace inside Held expression

I wish to make functional replacement inside Held expression like this: ...