Area under the curve in blocs

Hello, I would like to know the area under the curve in blocs from 1 to 2, 2 to 3, etc and also the total.

x = [1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40]
y = [816.347717738660	786.580796557696	363.851047832548	336.220017597815	158.261009949057	129.602592135761	108.274839017586	87.2792863693362	84.6981909884962	68.0648807629763	52.0965547430762	42.3375519238287	36.6589344217772	26.4122184741221	23.3209543975771	22.6645963300025	19.3563124261069	19.0505369873911	18.1401972796281	17.0982948804178	13.5394672532772	9.51007023669543	8.30033459487578	8.05732420060567	7.78827447107891	7.59211717172904	5.53294759143293	4.24011525196683	4.15026586159402	3.86071638283192	3.04425799381248	3.00408977428406	2.89234352480006	2.78175725105813	2.64856273269610	1.50102799563889	1.46442216474623	1.13604322104605	1.11244870832481	0.783468890092899]

areatotal = trapz(x,y)
area1 = trapz(x(1,1:2),y(1,1:2)) % First interval

Is there a better way to compute all the partial areas or i msut do 29 areas like i did for area1? giving every single interval

Thanks for your time

Answer 1

[KSSV]

Find it by intervel:

x = [1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40] ;
y = [816.347717738660	786.580796557696	363.851047832548	336.220017597815	158.261009949057	129.602592135761	108.274839017586	87.2792863693362	84.6981909884962	68.0648807629763	52.0965547430762	42.3375519238287	36.6589344217772	26.4122184741221	23.3209543975771	22.6645963300025	19.3563124261069	19.0505369873911	18.1401972796281	17.0982948804178	13.5394672532772	9.51007023669543	8.30033459487578	8.05732420060567	7.78827447107891	7.59211717172904	5.53294759143293	4.24011525196683	4.15026586159402	3.86071638283192	3.04425799381248	3.00408977428406	2.89234352480006	2.78175725105813	2.64856273269610	1.50102799563889	1.46442216474623	1.13604322104605	1.11244870832481	0.783468890092899] ;
areatotal = trapz(x,y) ;

A = zeros(length(x)-1,1) ; 
for i = 1:length(x)-1
    A(i) = trapz(x(i:i+1),y(i:i+1)) ; 
end

[Tiago Dias]

ok a loop it is. thanks