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Alan Stevens


Last seen: Today
126 total contributions since 2020

Alan Stevens's Badges

  • 3 Month Streak
  • Knowledgeable Level 3
  • First Answer

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Answered
x-intersection of part of extended line from curve
You can use the following relation: ( max(y_redline_value) - min(y_redline_value) ) / ( max(x_redline_value) - min(x_redl...

9 hours ago | 0

Answered
Using 'for' loop in integral correctly
Just define y as a function of t, B, a, b, and c, wihout regard to i. Then call the function with the appropriate parameters wh...

14 hours ago | 0

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Error with surf function
Try x = linspace(1,16,16); y = linspace(1,256,256); surf(x,y,data)

1 day ago | 1

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Solving second order non-linear equations (time-domain)
Here's the basic idea. First turn your second-order ODE into twofirst order ones, like so: Then structure your code along th...

2 days ago | 0

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Maximization function using linear programming
It's clear that the maximum of G will occur when D = 0.50 and eff = 0.75. Do a surf plot to convince yourself!

3 days ago | 0

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ODE Inverse Laplace Transformation Constants Error
The solution you think is correct does not satisfy the condition y`(0) = 0. It gives y`(0) = 9. MATLAB's solution satisfies bo...

3 days ago | 0

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Bisection method for transcendental equations. I:e tan(x)= x
If I were you I would change the "while" condition to while abs(x1-x2) > 0.0001

3 days ago | 0

Answered
How to find the angle in MatLab
atan(200/20) works perfectly well in Matlab. Note that the result is in radians. If you want the angle in degrees then multipl...

4 days ago | 0

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Answered
ode45 does not solve my second order problem
Your warnings occur when z(1) goes negative. They can be eliminated by including if z(1)<0 z(1) = 0; end at the beginn...

4 days ago | 1

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Answered
Comapring Values in one Matrix to another
What about: A = [373 383 393 403 413 420 451 485 499] ; B = [373 453 457 461 464]; k = 1; for i = 1:length(A) t = A(i); ...

4 days ago | 0

Answered
Plotting a function with vectors that show propagation of function.
Does this do what you want: X = linspace(-150,150,200); g2 = 5; g3 = 0.5; sigma0 = 0.05; B = -(3*g2*sigma0-8*g3*sigma0)...

4 days ago | 0

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Plotting a contour plot for a variable dependednt on the while loop
I'm not sure if I've interpreted your requirements correctly, but what about the following: %% Inputs IR = 1e-3; %initial ra...

4 days ago | 0

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Plotting a contour plot for a variable dependednt on the while loop
Your code doesn't stop because Vol never reaches zero. What does the c index do for you? Your contour function won't plot wh...

5 days ago | 0

Answered
How can i find the minimum value of spline data
Change your last two lines to: s=spline(x,y); min(ppval(s,x)) (though it's fairly clear that the minimum occurs at x = 0!)

5 days ago | 0

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Answered
To repeat calculation in a matrix
Do you mean you want the maximum of the rows in RAJ_Mx1 taking into consideration only those values where the corresponding ele...

5 days ago | 0

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Answered
help in plot of sin
Try t=0:1/(f*50):1/(f*0.5); instead of t=0:1/(f*5):1/(f*0.5);

5 days ago | 0

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How do I plot a univariate integral?
Like this (you will need to replace my arbitrary polynomial with your own): % Arbitrary polynomial p = [2 1 -1 3 1 -1 5]; fun...

5 days ago | 0

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How to convert a char into double?
Unfortunately, sscanf only gets the first 1863 numbers for some reason. The following gets them all: f = '92 -707 1349 92 -708...

5 days ago | 0

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Newton Raphson’s method
If we set f(x) = cos(x) + 2sin(x) + x^2, then the question is asking for the value of x that makes f(x) = 0. Newton-Raphson is ...

6 days ago | 0

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Calculate the distance between a linear regression line and the data points
If you have the x-values of all the data points of interest you can calculate the corresponding y-values of your line simply us...

7 days ago | 0

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Answered
fminbnd got stock in local minimum: can global search deal with the problem defined by cases?
Narrow the allowed search interval. If you've plotted the function you should be able to get a good idea of where the global mi...

7 days ago | 0

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Answered
How do I plot filled markers on top of two axis
Try changing the order: X = linspace(1,10,20); % Create axes ax1=gca; ax2=axes('Position',get(ax1,'Position'),'YAxisLocati...

7 days ago | 0

Answered
First Order Differential Equation
Try plot(t, Y(3:6,:))

8 days ago | 0

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First Order Differential Equation
Well, the following shows how to progress through time. However, the explicit form you've adopted is unstable. I've included a...

8 days ago | 0

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Answered
ode,dsolve,spline,ode interp, differantial
More like this perhaps: xspan = [0 3]; Q0 = 0; [x, Q] = ode45(@f, xspan, Q0); plot(x,Q), grid xlabel('x'), ylabel('Q'...

9 days ago | 0

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How to round number up to a specific number of decimal places?
ceil(10*x)/10

9 days ago | 0

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Vector dimensions in my ode
I think the following produces somewhat more sensible results. I was confused for some time because you use x for both distance...

9 days ago | 0

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Answered
Vector dimensions in my ode
The problem is here: f = @(t,x) [ x(2); -( k_s*(x(1)-h)/ m ) ]; When you call this function, x(2) is a single value, but since...

10 days ago | 0

Answered
help solving differential equations
I think the following does all that you want. My implementation of the legend is cumbersome, but works! % m*f'^2 -0.5(m+1)*f*f...

10 days ago | 0

Answered
Please help me convert equation to matlab code.
This does what you seemed to be trying to do:: pgridbuy = [3.3, 3.5, 3.2, 3.1, 3.6]; pgridsold = [2.3, 2.6, 3.1, 4.1, 4.4]; p...

10 days ago | 0

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