# How to integrate using trapz function

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shagun chaudhary on 31 Aug 2022
Commented: Bjorn Gustavsson on 31 Aug 2022
Hi I am using trapz to get my answer. but i am getting 0 which is not the answer. I have attched my data where Y reprsesnt loads (mg/hr) and x represents time in a number form . Please i will extremely graeful if somebody can help.
Int=trapz(X1,Y);

Bjorn Gustavsson on 31 Aug 2022
The variable in X1 seems awfully constant, at 0.0166. The first input to trapz should be the x-coordinate of the points at which you have Y, not the values of "dx". Perhaps what you want is something like:
Ival = trapz(cumsum(X1),Y);
HTH
Bjorn Gustavsson on 31 Aug 2022
If you look at the help for trapz you will read:
Z = trapz(X,Y,DIM) or trapz(Y,DIM) integrates across dimension DIM
of Y. The length of X must be the same as size(Y,DIM)).
That means that your call to trapz would be something like:
z_all = trapz(cumsum(X1),Y,2);

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