Can a function in matlab return a polynomial or an expression?

Say I want (3x-3) returned when 3 is given as an input parameter. How can I do this?

Answer 1

[Titus Edelhofer]

Hi,

if you are looking for polynomials only: polynomials of form a_n*x^n+ ...+a_1*x+a_0 are represented as vectors [a_n ... a_1 a_0], so in your case simply [3 3].

Take a look at the functions working with polynomials (at the bottom of):

doc polyfun

Titus

Answer 2

[Torsten]

    if Input == 3
        f=@(x)(3*x-3);
    end

Best wishes

Torsten.

Answer 3

[Guillaume]

Your question is too open ended to be answered properly. What do you want to do with the return value? What does (3x-3) mean to you? How is it even constructed (do you always want a polynomial of degree 1 with all coefficients equal to the input?). Depending on the answer to these questions

• You could return a function handle, as in Torsten's answer.
• You could return a vector of polynomial coefficients to be evaluated with polyval.
• You could just return the string '3x-3', which you could construct any number of ways (with sprintf or num2str or ...)
• You could return something else