Rafael Hernandez-Walls

Last seen: 4 jours ago

1 312 total contributions since 2010

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

Rafael Hernandez-Walls's Badges

Answered
Change the sign of a Vector over N intervals
Use something like this: Y=rand(1,20); d=[1:4,8:12,17:20]; Y(d)=-Y(d)

13 jours ago | 0

Answered
For loop only outputting the final value.
Try using something like this: t=linspace(0,3*pi,100) t=linspace(0,3*pi,100); for k=1:length(t) y = q2(t(k)); val...

22 jours ago | 0

Answered
Plotting log x and y
Why don't you treat like this: n = 30; x = 0.5; h(1) = 1; emin = 1; for i =1:n if i==1 h(1)=0.5; else ...

environ 2 mois ago | 0

Solved

Mass Conversion 2

3 mois ago

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Calculate the answer to life the universe and everything
<https://en.wikipedia.org/wiki/42_(number)>

3 mois ago

Solved

How many hours are there in a day in Italy?
Remember "European Summer Time"

3 mois ago

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Temperature Conversion 3

3 mois ago

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Temperature Conversion 2

3 mois ago

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Temperature Conversion 1

3 mois ago

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Simpsons's rule (but not Homer Simpson)
I wonder what Homer Simpson would have thought of Simpson's rule? Somehow I doubt his thoughts would have included the phrase Ne...

4 mois ago

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Total energy

4 mois ago

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Potential energy calculation

4 mois ago

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Kinetic energy calculation

4 mois ago

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Laws of motion 7

4 mois ago

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Laws of motion 6

4 mois ago

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Laws of motion 5

4 mois ago

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Laws of motion 4

4 mois ago

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Laws of motion 3

4 mois ago

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Laws of motion 2

4 mois ago

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Laws of motion 1

4 mois ago

Answered
How can i draw the graph of this two functions using matlab
when i have this like problem i use this code: t=linspace(0,2*pi,50); f=((t>0)&(t<=1)).*2+((t>1)&(t<=pi/2)).*0.5.*t.^2+((t>pi...

4 mois ago | 0

Answered
Finding the length of square function
t2=t(find(diff(X)>0)); t1=t(find(diff(X)<0)); long_time=t2(2)-t1(2)

4 mois ago | 0

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How to create a sine wave with variable frequency - Simulink
something like this: (?) t=linspace(0,2*pi,100); f=rand(1,100); y=sin(f.*t); plot(t,y)

4 mois ago | 0

Answered
Euler method returning error
maybe you need copy the function eulsys.m in your system. In this link you have a copy: http://macs.citadel.edu/chenm/344.dir/0...

4 mois ago | 0

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how do i plot only certain part of cepstrum
KSSV ks suggests that you work with the index, here I show you an example of what KSSV mentions, x=linspace(0,10,100); y=x.^2;...

4 mois ago | 0

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Answered
How do I resolve this stability criterion question?

5 mois ago | 0

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creating multiple values of the same x,y,z
x=[ 2, 4, 2]; repmat(x,10,1)

5 mois ago | 0

| accepted

Answered
no data plots on graph (plot (x,y))
David is correct. Why don't you try something like that in your code... d(1) = 32000; H = 8000; Re = 6370000; %c2 = 0.5*exp(...

5 mois ago | 0

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Answered
Invalid syntax error with a simple code
tray this x = [-2 -1.5 -1 -0.5 0 0.5 1 1.5 2]; y = (x+x.*(sqrt(x+3))).*(1+2*(x.^(2)));

5 mois ago | 0

| accepted

Answered
How can I obtain slope of a trend line calculated for a time serie
Maybe this is useful for you https://www.mathworks.com/help/matlab/ref/detrend.html

5 mois ago | 0