Write a MatLab user-defined function that determines the coefficients of a cubic polynomial, ƒ(x)=a₂x³ + a₂x² + a₁x + a that best fits a given set of data points. The function should also calculate the overall error E. Name the function [a,Er] = CubPolFit(x,y), where the input arguments x and y are vectors with the coordinates of the data points, and the output argument a is a four-element vector with the values of the coefficients a3, a₂, a₁, a. The output argument Er is the value of the overall error. (a) Use CubPolFit to find the cubic polynomial that best fits the data in the rubber tension tests (see lecture slides): Curve fitting - polynomial regression - Example A tension test is conducted for determining the stress-strain be- havior of rubber. The data points from the test are shown in the figure, and their values are given below. Determine the fourth order polynomial that best fits the data points. Make a plot of the data points and the curve that corresponds to the polynomial. Strain € Stress o (MPa) Strain € Stress o (MPa) 0 0.4 0.8 1.2 1.6 2.0 2.4 0 3.0 4.5 5.8 5.9 5.8 6.2 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6 6.0 7.4 9.6 15.6 20.7 26.7 31.1 35.6 39.3 41.5 40 36 Strain 6 6 2 (b) Write a program in a script file that plots the data points and the curve of the cubic polynomial that best fits the data.

X is a vector,  X = -5:0.5:5; please do part a and b on matlab

Play and practice all the functions that we listed here.  What I would like you to do is to first create three vectors---a logic vector, a double vector, and a character vector, for example, x1 = c( TRUE, FALSE, TRUE) x2 = c( 0, -2.5, 1, 3, 5.9 ) x3 = c( "a1", "a2", "za", "zz", "0", "1") and apply each function to all three vectors to see what would happen. If the function requires more than one input x, then you just create other objects as needed. sum (x) sum of the elements of x prod (x) product of the elements of x max (x) maximum of the elements of x min(x) minimum of the elements of x which. max (x) returns the index of the greatest element of x which. min(x) returns the index of the smallest element of x range (x) id. than c (min(x), max (x)) length (x) number of elements in x mean (x) mean of the elements of x median (x) median of the elements of x   round (x, n) rounds the elements of x to n decimals rev…

make a code , if you can uses mathlab keep basic code no if or return