Area under a curve using trapz method

Hello, hope everyone is well. I have combined two graphs together to get a side by side comparison of them and now I am after trying to get the area under the curve using the trapz method for both data sets.

Since my data has positive and negative values, I have trying to use this code to develop a answer but I am unsure if it is correct or not:

Ak = trapz(f2c(10:50)) - trapz([50 90],[f2c(50) f2c(90)]);
Au = trapz(f2u(10:50)) - trapz([50 90],[f2u(50) f2u(90)]);
or is this code more applicable?
Ak = trapz(f2c(10:35)) + trapz(f2c(35:70));
Au = trapz(f2u(10:35)) + trapz(f2u(35:70));

Ak being the uncalibrated set and Au being the uncalibrated set. I would highly appreciate any comments or guidance please. & thank you in advance.

[KSSV]

You can use trpz for the complete datasets with range. You need not to go by signs.

[fabian Maritato]

do you mean I can just do:

ak = trapz(f2c)
au = trapz(f2u)

and that take the whole data set range?

[KSSV]

Yes.

[fabian Maritato]

Thank you. Say, Also if I have two sets of calibrated data sets, say f1c & f2c and want to do a trapz function between those, where the graphs are similar to each other. Would I need to add them together or just:

Ak = trapz([f1c,f2c]);

be the correct way of doing so?

[KSSV]

Do them separately.