# Rafael Hernandez-Walls

Last seen: 7 dagen ago Active since 2010

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

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Swap between first and last column
The idea is to swap between first and last column Ex = [1 2 3 4 5; 1 2 3 4 5; 1 2 3 4 5; 1 2 3 4 5; 1 2 3 ...

25 dagen ago

Solved

Remove a specific row with max value
Remove the row that contain the max value in the matrix? If you like the problem, please like it :)

25 dagen ago

Solved

Swap between rows
The idea is to swap between second and second last row Ex = [1 2 3 4 5; 5 4 3 2 1; 1 2 3 4 5; 1 2 3 4 5; ...

25 dagen ago

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Count consecutive 0's in between values of 1
So you have some vector that contains 1's and 0's, and the goal is to return a vector that gives the number of 0's between each ...

4 maanden ago

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Molar Air Density from Temperature and Pressure
The molar density of air can be found from the Temperature and Pressure using the ideal gas law. where the Molar density STP ...

meer dan een jaar ago

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Calculate Wind Chill Factor
The NWS Wind Chill Temperature (WCT) index formula for calculating the dangers from winter winds and freezing temperatures: Cal...

meer dan een jaar ago

Solved

Air Mass to Star for an Observer at Mean Sea Level
Air mass is a measure of how much atmosphere light from a source above the atmosphere (eg sun, planet, star) has to travel throu...

meer dan een jaar ago

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Find Air Temperature from Cricket Stridulation Rate
Stridulation is the process that creates a cricket's “chirp” by rubbing their wings or legs. According to the Old Farmer's Alma...

meer dan een jaar ago

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Construyendo matrices parte 2
Construye la siguiente matriz a partir de otros tres vectores/matrices. [ 1 8 15 3 3 3 3 2 9 16 3 3...

meer dan een jaar ago

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Sum of series IV
What is the sum of the following sequence: Σ(-1)^(k+1) (2k-1)^2 for k=1...n for different n?

meer dan een jaar ago

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Back to basics 22 - Rotate a matrix
Covering some basic topics I haven't seen elsewhere on Cody. Rotate the input matrix 90 degrees counterclockwise (e.g. [1 2; ...

meer dan een jaar ago

Solved

Composite Trapezoidal Rule for Numeric Integration
Use the trapezoidal rule to numerically integrate a function, _f(x)_, passed as the first argument, between upper and lower limi...

meer dan een jaar ago

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Differential equations I
Given a function handle |f| an initial condition |y0| and a final time |tf|, solve numerically the differential equation dy...

meer dan een jaar ago

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Weighted Convolution
Given two input vectors x = [x_1, x_2, ..., x_K] and y = [y_1, y_2, ..., y_K] of equal length, compute the weighted convolution ...

ongeveer 2 jaar ago

Determine if any key is being pressed
If only use the function: pause

meer dan 2 jaar ago | 0

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The Piggy Bank Problem
Given a cylindrical piggy bank with radius g and height y, return the bank's volume. [ g is first input argument.] Bonus though...

meer dan 2 jaar ago

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mathematics , probability problem
How many different result can we have, rolling k dice?

bijna 3 jaar ago

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MATLAB Basics: Complex Conjugates
For a given complex number, x, return the complex conjugate, y.

bijna 3 jaar ago

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MATLAB Basics: Complex Numbers
For a given complex number, x, return the real and imaginary parts as a vector, y = [Real Imaginary].

bijna 3 jaar ago

Solved

Flip coins

bijna 3 jaar ago

Solved

Normalizing a vector

bijna 3 jaar ago

Solved

Return fibonacci sequence do not use loop and condition
Calculate the nth Fibonacci number. Given n, return f where f = fib(n) and f(1) = 1, f(2) = 1, f(3) = 2, ... Examples: ...

bijna 3 jaar ago

Solved

Number of Even Elements in Fibonacci Sequence
Find how many even Fibonacci numbers are available in the first d numbers. Consider the following first 14 numbers 1 1 2...

bijna 3 jaar ago

Solved

Find the next Fibonacci number
In the sequence of Fibonacci numbers, every number is the sum of the two preceding ones: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55...

bijna 3 jaar ago

matlab not plotting graph
You need one point in the equation of z h = [2,4,6,8,10]; x = 10.1; y = 2.5; z = (x * h.^2 - x - sqrt(y^2*h.^2 - y^2))./ (h....

bijna 3 jaar ago | 0

Solved

Mass Conversion 1

bijna 3 jaar ago

how i can find the chessboard lines and draw on the main image with any solution

bijna 3 jaar ago | 0

how can I get y which correspond to x and then plot (x,y)??
Try this: x=linspace(-4,4); for r=1:length(x) y(r)=fzero(@(y)y.^3+0.2*exp(-1*x(r).^2)*y.^2-2.2039*y.^2+0.8155,1); end p...

bijna 3 jaar ago | 0