How do I find polygonal curve length?

My problem is to write a function to compute the length of a polygonal curve whose ith vertex has Cartesian coordinates x(i) and y(i). x and y must be row or column vectors of the same size.

Answer 1

[Image Analyst]

Can't you use the Pythagorean theorem:

% Some data... however you got it.
x = rand(1, 5);
y = rand(1, 5);
% Get delta x and delta y.
dx = abs([diff(x), x(end)-x(1)])
dy = abs([diff(y), y(end)-y(1)])
% Find distances between vertices
distancesBetweenVertices = sqrt(dx.^2 + dy.^2)
% Sum all the sides to get the total perimeter.
perimeter = sum(distancesBetweenVertices)

[Jim Oste]

How would I go about finding the x and y coordinates of a given function?

[Image Analyst]

You can write a couple of lines of code. For example to find x and y for a quadratic function between x=-5 and 5, with 31 coordinates, do this:

x = linspace(-5, 5, 31);
y = a * x.^2 + b * x + c;  % You define a, b, anc c before this.