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# Rafael Hernandez-Walls

##### Last seen: Today
1.122 total contributions since 2010

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

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How long does it take to run a bath?
Given the *volume flow rate* (volume/time) of a faucet and the *volume* of a bath tub, find the amount of time it takes to fill ...

2 Tage ago

Solved

R2012b atan in Degrees
Return in degrees the atan result of inputs for all four quadrants. *Examples:* [x, y] Degrees 1 0 0 1 1 ...

2 Tage ago

finding all indices of a value in matrix
A=[2 2 3 ; 2 4 2; 2 3 2]; [r,c]=find(A==min(A))

3 Tage ago | 0

| accepted

Solved

Remove duplicated triangles
Input T is a triangulation (triplet list of indices -positive integers-, each index refering to a vertex number in a correspondi...

2 Monate ago

Solved

Weighted moving average
x1=[1 2 1]; y1=[1 2 2 4 5 6 6 8]; Make function for weighted moving average. z(i)=(x1(i)*y1(i)+x1(i+1)*y1(i+1)+x1(i+2)*y1...

3 Monate ago

Solved

Height of a right-angled triangle
Given numbers a, b and c, find the height of the right angled triangle with sides a and b and hypotenuse c, for the base c. If a...

3 Monate ago

Solved

Separate even from odd numbers in a vector - with a loop
*Using a loop*, rearrange a vector of integers such that the odd numbers appear at the beginning, and even numbers at the end. T...

3 Monate ago

Solved

Angle of triangle
For three unknown points a b c, given three sides ab bc ca, find three angles abc bca cab in radians. Your function should b...

3 Monate ago

Solved

Find the Oldest Person in a Room
Given two input vectors: * |name| - user last names * |age| - corresponding age of the person Return the name of the ol...

3 Monate ago

Solved

Compute Fibonacci Number
Compute the _n_-th Fibonacci Number f(0) = 0, f(1) = 1, f(2) = 1, f(3) = 2, ... f(42) = 267914296

3 Monate ago

Solved

Given a 4x4 matrix, swap the two middle columns
If a = [1 2 3 4; 1 2 3 4; 1 2 3 4; 1 2 3 4]; then the result is ans = 1 3 2 4 1 3 2...

3 Monate ago

Solved

Can we make a triangle?
Given three positive number, check whether a triangle can be made with these sides length or not. remember that in a triangle su...

3 Monate ago

Solved

Divisible by 10
Pursuant to the <http://www.mathworks.com/matlabcentral/cody/problems/42404-divisible-by-2 first problem> in this series, this o...

3 Monate ago

Solved

Perimeter of a semicircle
Given the diameter d, find the perimeter of a semicircle

3 Monate ago

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Write a function man that takes a row vector v and returns a matrix H as follows..
Write a function called man that takes a row vector v as an input and returns a matrix H whose first column consist of the eleme...

3 Monate ago

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Get all prime factors
List the prime factors for the input number, in decreasing order. List each factor. If the prime factor occurs twice, list it as...

3 Monate ago

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Calculate Inner Product
Given two input matrices, |x| and |y|, check if their inner dimensions match. * If they match, create an output variable |z|...

3 Monate ago

Solved

Solve a System of Linear Equations
*Example*: If a system of linear equations in _x&#8321_ and _x&#8322_ is: 2 _x&#8321;_ + _x&#8322;_ = 2 _x&#8321;...

3 Monate ago

Solved

Convert from Fahrenheit to Celsius
Given an input vector |F| containing temperature values in Fahrenheit, return an output vector |C| that contains the values in C...

3 Monate ago

Solved

another bullseye
create matrix like below -- for x=2, y=[1 1 1 1 1; 1 2 2 2 1; 1 2 3 2...

3 Monate ago

Array indices must be positive integers or logical values. Error in (line 8) mr(t)=mi-((mi-mf)*(t./tb));
Hi, Yo have 2 errors. First you have the line when you define the vector time: t=linspace(6.5,164,1) % You need to put the n...

3 Monate ago | 1

Solved

Given a and b, return the sum a+b in c.

3 Monate ago

Solved

In this problem, you have to add three numbers a, b and c. Give output d = add(a,b,c)

11 Monate ago

Solved

Angle between two vectors
Given 2 pairs of _cartesian co-ordinates_, determine the angle between the 2 vectors formed by the _points_ and the _origin_. An...

11 Monate ago

Solved

UICBioE240 problem 1.7
Find the other two angles of a right triangle given the two of the sides. So if A = [1 1] B = [45 45]

etwa ein Jahr ago

Solved

Kepler's Equation
Solve <http://en.wikipedia.org/wiki/Kepler's_equation Kepler's Equation>. Note that the solution is rounded down to 5 decima...

etwa ein Jahr ago

Solved

Sum of diagonals elements of a matrix
Given a matrix, return the sum of all the elements across the diagonals. E.g. A = [1 2 3; 4 5 6; 7 8 9;...

etwa ein Jahr ago

Solved

Set x value to each odd index of vector y.
Set x value to each odd index of vector y.

etwa ein Jahr ago

Solved

Scalar Matrix Manipulation
Assume, input x is a scalar matrix such as, x = 2 0 0 0 2 0 0 0 2 th...

etwa ein Jahr ago

Solved

Vector LCM
* Find Least Common Multiple of a given vector. * Need general solution as the test suite will be expanded. * Function Templa...

etwa ein Jahr ago