MATLAB: Is the derivative of a function or signal one sample shorter that the orignal

Question

Hi All

taking the derivative of y=x.^2 using diff(y) , between 0 and 100 gives a signal with one less Sample, meaning instead of length of 101, it is 100 samples. so every derivative, it will get one sample shorter and if I have to integrate again, it will need those samples again maybe ? what should I do ?

Answer 1

Use the gradient function to calculate the numerical derivatives. The output will be the same length as the input. (It is also more accurate in that respect.) The function assumes regularly-sampled data, however if the sampling intervals are not constant, a work-around for that is:

dydx = gradient(y) ./ gradient(x);

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