How to calculate area under curve.

So, I am trying to get an area under curve (shaded area) shown above,

Assuing the boundry is "a" and "b", how could I calculate this area under curve?

[James Tursa]

If you have functions defining a and b, simply integrate a - b. How are a and b defined? Functions, or data points, or ...?

[Sun Kyoo Choi]

Everything is in data points.

So, basically, I imported from the excel datasheet and extracted to MATLAB.

Also, I know a and b values.

How would the code look like?

Answer 1

[Ameer Hamza]

If the curve is available as datapoints, then you can use trapz(): https://www.mathworks.com/help/matlab/ref/trapz.html

For a specific example, please share the datapoints as a mat file.

[Sun Kyoo Choi]

Here you go.

[Ameer Hamza]

This approximates the area in the given region.

mask = 9.4 < B & B < 13.1;
A_ = A(mask);
B_ = B(mask);
trapz(B_, max(A_)-A_)

[Sun Kyoo Choi]

Thank you:)

[Ameer Hamza]

Glad to be of help.

Answer 2

[KSSV]

Read about polyarea