Evaluate f(x) for multiple evenly spaced values

How do I evaluate a function f(x) for multiple, evenly spaced values of x between two variables. ie x = exactly 10 evenly spaced numbers between 5 and 20

I'm thinking define an anonymous function so I can evaluate it over a range of values but how to set those values is where I'm lost

Answer 1

[Shashank Prasanna]

x = linspace(5,20,10); % Generate 10 evenly spaced points between 5 and 20

y = f(x); % Call your function, assuming you have defined it already
%If f can't take in a vector you will have to call it in a loop.

[Josh]

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) >>

[Youssef Khmou]

Josh, to use mpower in your example, you must use elementwise :

 f=@(x) x.^3-2*x.^2-3*x+1
 x=linspace(5,20,10);
 y=feval(f,x)

[Image Analyst]

Josh, you have to do y=f(x), not f(x)=y. The "target" variable is on the left, and the expression on the right is evaluated and stuffed into the variable on the left. This is how every programming language that I've used does it.

Answer 2

[Youssef Khmou]

hi,

You can set the values using 'linspace' :

 x=linspace(5,20,10);
 f=@(x) sin(x)

 y=feval(f,x);

[Youssef Khmou]

linspace(a,b,n) generates a vector of n points linearly spaced between and including a and b .