How do I use a vector to evaluate a polynomial function?

I have a vector of x values that I need to plug into a cubic polynomial. And I keep getting errors

how exactly do I do this? The function is a polynomial and I keep getting errors

??? Undefined function or variable 'y'.

Error in ==> at 21 f(x)=y

OR

??? Error using ==> mpower Inputs must be a scalar and a square matrix.

Error in ==> @(x)x^3-2*x^2-3*x+1

Error in ==> at 21 y=feval(f,x) >>

Answer 1

[Shashank Prasanna]

You haven't show us how you are calling this function, that would give this question more clarity. In any case if you are calling the function with a vector input you will have to use the "." (dot) notation as below

x = rand(10,1); % some random numbers

f = @(x)x.^2 - 2*x.^2-3*x+1

y = f(x);

[Shashank Prasanna]

Josh, please share the exact implementation of your function, it will be easier to assist you if the above doesn't work.