Calculate area between y = 0 and the curve plotted by discontinuos data

Hi,

I have a curve like graph. I want to calculate the area between y = 0 and the curve ploted by discontinuous data.

Could you have any suggestions?

Answer 1

[KSSV]

As you have data (x,y) in your hand use trapz(x,y) (Trapezoidal numerical integration) to get the area. doc trapz..

Eg:

X = [0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85];
rA = [-.0053, -.0052, -.0050, -.0045, -.0040, -.0033, -.0025, -.0018, -.00125, -.0010];
plot(X,-1./rA,'.-r')
% Area 
Int = trapz(X,rA)