How can I solve this: (x-2)*(x+1)^3?

Hey there,

I am trying to process this "(x-2)*(x+1)^3" through matlab in way that I can have a result like this:

However every time I try to perform this operation, matlab keeps on telling me that x is set to nothing, how can I solve this?

Thanks in advance!

Answer 1

[Ayaz Siddiqui]

Try using expand.

syms x;
expand((x-2)*(x+1)^3)

[LUCA GIROTTI]

Thank you so much @Ayaz Siddiqui

Works perfectly !

Answer 2

[Sam Chak]

Hi @LUCA GIROTTI

It's good to hear that you tried working out something by yourself. You need to create a symbolic variable for x.

syms x

For more info, please check:

https://www.mathworks.com/help/symbolic/create-symbolic-numbers-variables-and-expressions.html

[LUCA GIROTTI]

Thank you for your answer @Sam Chak

I tried using "syms x" however thats the result I have (with this input (x-2)*(x+1)^3) :

(x + 1)^3*(x - 2)

Much better since I indeed don't have an error anymore, however it hasn't fully performed the operation.

[Sam Chak]

Hi @LUCA GIROTTI

Good to hear that. If you are dealing with algebraic expressions and analytical problems, you will be using syms a lot! You can find lots of examples and learn a lot of functions here to perform many types of symbolic computations:

https://www.mathworks.com/help/symbolic/performing-symbolic-computations.html