Find the area under a certain section of a plot

I have a set of data that I have used to plot the graph below. I am needing to find the area of the shaded area but cannot work out how to as I do not know what range of values make up this section and, as the data loops round multiple times there will be a few sets. The data used was two 2000x1 double vectors. Any help would be appreciated.

Note: The shading was done in photoshop as I do not know how to do this in Matlab earlier.

Answer 1

[Samatha Aleti]

You can do this by finding the points of intersection of the curve(y1) and the line(y2). Let the intersection points be “[x1,y1]” and “[x2,y2]”. You can find the area using "integral" function.Here is a sample code:

 x1 = 1; % Let
 x2 = 5; % Let
xmin = min(x1,x2); 
xmax = max(x1,x2); 
y1 = @(x) (x.^2)+2;  % Curve 
y2 = @(x) 2*x; % Line 
fun = @(x) ((x.^2)+2 - 2*x);  % y1-y2 
area = integral(fun,xmin,xmax);