How to get back the values of a curve from its cumulative integral value?

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AS 2021-4-5

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评论： AS 2021-4-7

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I have a amplitude distribution with time ( i.e. real curve, blak line). Then I did cumulative trapezoidal inegration of the curve using cumtrapz, which is represented by blue curve. Now, I again retain the real curve i.e. black curve from its cumulative integration i.e. blue curve. How I will get the real curve? Please provide me the suggestions. Thanks in advance.

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darova 2021-4-5

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Use diff to find real curve from cumulative trapezoid result

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darova 2021-4-7

在 MATLAB Online 中打开

data.txt

Works ok for me

clc,clear
y = load('data.txt');
x = 1:length(y);
inty = cumtrapz(x,y);
y1 = diff(inty)./diff(x);
plot(x,y,'r')
line(x,inty,'color','k','linestyle','--')
line(x(2:end),y1)
legend('original','returned')