Community Profile

photo

Rafael Hernandez-Walls


Last seen: Today
1,276 total contributions since 2010

My interest is everything related to numerical schemes applied to PDE and Oceanography, UABC.

Contact

Rafael Hernandez-Walls's Badges

  • Scavenger Finisher
  • Knowledgeable Level 2
  • Revival Level 1
  • 3 Month Streak
  • Community Group Solver
  • Introduction to MATLAB Master
  • Project Euler I
  • Personal Best Downloads Level 1
  • First Submission
  • Cody Problems in Japanese Master
  • Draw Letters
  • Leader
  • Scholar
  • Promoter
  • Creator

View all

Contributions in
View by

Answered
Converting Euler's method calculation into matlab
tray this: % Initial conditions and setup Q=400; A=1200; alph=160; h = 0.5; % step size t = 0:0.5:10; % the range of t ...

18 hours ago | 1

| accepted

Answered
Lotka-Volterra Predatir Prey Model Code
using this: function [dPdt] = lotkavolterra(t,P) alpha = 1.5; % you have error here: you using alpa beta = 1; gamma = 3; de...

18 hours ago | 0

| accepted

Solved


Counting Sequence
Given a vector x, find the "counting sequence" y. A counting sequence is formed by "counting" the entries in a given sequence...

14 days ago

Answered
¿Por qué mi código no corre?
Hola, Creo que tu condicion incial debe ser de solo dos elementos y no de tres. Intenta este programa principal, el cual llamará...

22 days ago | 0

Solved


Triangle of numbers
Create a matrix with the integers from 1 to |n| arranged in a triangular shape. Every row |i| of the matrix contains |i| inte...

22 days ago

Answered
How do I plot a function that has been split into multiple time intervals
I don't know if I understand your problem, but I think it is related to the way to program the following code: t=-1:0.1:6; y...

23 days ago | 0

Solved


Back to basics 2 - Function Path
Covering some basic topics I haven't seen elsewhere on Cody. Given a string that is the name of a MATLAB function, return a s...

23 days ago

Solved


Prime factor digits
Consider the following number system. Calculate the prime factorization for each number n, then represent the prime factors in a...

24 days ago

Answered
hi I am trying to calculate the 4th root of the function f(x)=3x4+7x3−4x2−10x+15 using newtons method and a for - loop
clear clc close all % function f = @(x) 3*x.^4 + 7*x.^3 - 4*x.^2 - 10*x + 1/5; % derivative df = @(x) 12*x.^3 + 21*x.^2...

27 days ago | 0

Answered
Making combinations using random number generators
N=input('give me number of random elements:'); a=input('lower limit of the numbers to generate:'); b=input('upper limit of the...

28 days ago | 0

| accepted

Answered
How to create a noisy signal for wavelet transform practice?
maybe this code will help you N=1000; x=linspace(0,2*pi,N); y=sin(x); y2=randn(1,N); y3=y+y2*.1; subplot(2,1,1);plot(x,y)...

1 month ago | 1

| accepted

Solved


Given a matrix A return a vector of the product of the elements in each column using a loop without using prod.
--------------------- for m: 3 1 3 3 10 1 9 1 9 4 1 4 5 6 5 ...

1 month ago

Solved


Product of Each Column
Given a matrix |mat| with |n| columns, return a row vector |v| of length |n|, where every element in |v| is the product of the |...

1 month ago

Solved


Replace Nonzero Numbers with 1
Given the matrix x, return the matrix y with non zero elements replaced with 1. Example: Input x = [ 1 2 0 0 0 ...

1 month ago

Answered
Euler's Method
for n = [10, 20, 40, 80, 160] a = 0; b = .5; c = .25; x = linspace(a,b,n);%[a:n+1:b]; f = x.^3; dx = x(...

1 month ago | 0

Answered
plotting for cosine wave
I change some lines.... N=45; theta=0:360; % range of values of theta Na1=2*N*cosd(theta); % cosd for cos when you use de...

2 months ago | 0

Answered
Solving a simple integral with input equation from user
syms x str = input('Enter an equation in x: ','s') ; f = function_handle.empty; f = eval(['@(x)', str]); %x = f(); xmin= ...

2 months ago | 1

| accepted

Solved


Area of a pentagon
Given the side of a regular pentagon and its apothem return the area of pentagon. Remember the area of pentagon is calculate ...

2 months ago

Solved


Find the area of ​​the square
There are *n²* circles inscribed in the square ABCD. The perimeter of each circle is *aπ* <<http://imgfz.com/i/3wzCeAT.png>> ...

2 months ago

Solved


Times 5
Try out this test problem first. Given the variable x as your input, multiply it by five and put the result in y. Examples...

2 months ago

Solved


Times 10
Try out this test problem first. Given the variable x as your input, multiply it by ten and put the result in y. Examples:...

2 months ago

Solved


Doubling elements in a vector (★★)
(copy of prob. 1024) Given the vector A, return B in which all numbers in A are doubling. So for: A = [ 1 5 8 ] t...

2 months ago

Solved


Mo money, mo math #2! (★★★)
(adapted from Prob 9 Cody team) You have a matrix for which each row is a person and the columns represent the number of quar...

2 months ago

Solved


Sort even numbers from 1 to 100
Sort even numbers from 1 to 100 for ex: x=1:100

2 months ago

Solved


Sum of terms in a series 1 (★★★)
Given x and n, compute the following sum: |x|+|x|^(1/2)+|x|^(1/3)+|x|^(1/4)+|x|^(1/5) ... + |x|^(1/n) where ||x|| indica...

2 months ago

Solved


Power Numbers
Find the n-th power of m.

2 months ago

Solved


Sum 1 to 100 even number
Write a Matlab program to add all the even numbers from 0 to 100 |

2 months ago

Solved


How tall are you?
measures your height forexample= 175cm 180cm 169cm

2 months ago

Solved


Times 11
Try out this test problem first. Given the variable x as your input, multiply it by eleven and put the result in y. Exampl...

2 months ago

Load more