derivative

I've found polynomial coefficients from my data: R <- c(0.256,0.512,0.768,1.024,1.28,1.437,1.594,1.72,1.846,1.972,2.098,2.4029) Ic <- c(1.78,1.71,1.57,1.44,1.25,1.02,0.87,0.68,0.54,0.38,0.26,0.17) NN <- 3 ft <- lm(Ic ~ poly(R, NN, raw = TRUE)) pc <- coef(ft) So I can create a polynomial function: f1 <- function(x) pc[1] + pc[2] * x + pc[3] * x ^ 2 + pc[4] * x ^ 3 And for example, take a derivative: g1 <- Deriv(f1) How to create a universal function so that it doesn't have to be rewritten for every new polynomial degree NN ? My original answer may not be what you really want, as it was

I have two arrays x and y as : x = np.array([6, 3, 5, 2, 1, 4, 9, 7, 8]) y = np.array([2, 1, 3, 5, 3, 9, 8, 10, 7]) I am finding index of local minima and maxima as follows: sortId = np.argsort(x) x = x[sortId] y = y[sortId] minm = np.array([]) maxm = np.array([]) while i < y.size-1: while(y[i+1] >= y[i]): i = i + 1 maxm = np.insert(maxm, 0, i) i++ while(y[i+1] <= y[i]): i = i + 1 minm = np.insert(minm, 0, i) i++ What is the problem in this code? The answer should be index of minima = [2, 5, 7] and that of maxima = [1, 3, 6] . You do not need this while loop at all. The code below will give

I am looking for a method to compute a derivative using a discrete and fast method. Since now I do not know the type of equation I have, I am looking for discrete methods analog to the ones that we can find for the integral such as, the Euler method. Andrea Ambu I think you are looking for the derivative calculated in a point. If this is the case, here there is a simple way to do that. You need to know the derivative in a point, say a . It is given by the limit of the difference quotient for h->0: You actually need to implement the limit function. So you: Define an epsilon, set it more small

I have the following function (Viviani's curve): Phi = @(t)[ cos(t)^2, cos(t)*sin(t), sin(t) ] Just a check that it's valid: s = linspace(0,T,1000); plot3(cos(s).^2, cos(s).*sin(s), sin(s)); How to derivate the function Phi (maybe multiple times), which represents Viviani's curve in a point t where t goes from 0 to 2*pi ? Did I defined Phi suitable for such a derivative? I've tried diff , but it did not keep the Phi as I would need it. If the second derivative would be Phi_d2 , I need to get it's value (for example in t = 0 ). How can I achieve this? Here are three ways you can accomplish this