# How do i do the reverse from expand function ?

15 visualizaciones (últimos 30 días)
tomer gigi el 12 de Nov. de 2021
Editada: Stephen23 el 23 de Mzo. de 2024
I have an expression lets say
a^2_2*a*b+b^2+b
and i want to simplify the expression to get
(a+b)^2+b
what is the proper way of doing this ?
##### 0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

### Respuestas (1)

Chidvi Modala el 19 de Nov. de 2021
Hi Tomer,
In general, you may use simplify(expr) function to perform algebraic simplification of expr. But simplify currently has some known issue with the simplification of sums. It cannot simplify your entire expression "a^2+2*a*b+b^2+b", but it can simplify "a^2+2*a*b+b^2" to "(a+b)^2". You may use the following example as a workaround.
syms a b;
simplify(expand(a^2+2*a*b+b^2)) + b
##### 3 comentariosMostrar 1 comentario más antiguoOcultar 1 comentario más antiguo
John D'Errico el 23 de Mzo. de 2024
No. Simplify still does not see how to return a partially factored result. I would have tried this:
syms a b
expr = a^2+2*a*b+b^2+b;
simplify(expr,steps = 1000,All = true)
ans =
as the standard way to solve it using simplfy, to see if it would find an alternate form.
But as you can see, it finds no "simpler" way to write that expression. The above was done using the Matlab version in Answers of R2023b.
Stephen23 el 23 de Mzo. de 2024
Editada: Stephen23 el 23 de Mzo. de 2024
It all depends on what metric you are using to define the term "simpler". According to some metrics you might come up with, using the parentheses could be considered more complex:
Expecting a computer to read minds and replicate nebulous human concepts... perhaps we need to involve some AI engine here: proposed new AI-based command SHOWMETHISLIKEIWOULDSEEITINATEXTBOOK().

Iniciar sesión para comentar.

### Categorías

Más información sobre Polynomials en Help Center y File Exchange.

R2020b

### Community Treasure Hunt

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

Start Hunting!

Translated by