I have an array $A$ having the next 145 values

I would like to calculate the $\frac{dA}{dX}$, having a 1D grid, $x$: 1:286:41468

DA_DX = gradient(A, 41468/145)


I am trying to understand why the $\frac{dA}{dX}$ output graph has peaks which cause problems to my code. Please, do you see something wrong in my steps? Is any other way to calculate the $\frac{dA}{dX}$ without gradient function?

dA = diff(A) / 286