Answered
What is wrong with my code?
R = 8.314; T1 = 60 + 273.15; PvapH = .7583; PvapT = .3843; HvapH = 29000; HvapT = 31000; P = .7; fPva...

4 years ago | 0

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Answered
Solving System of Equations with Symbolic Toolbox
Say you want to solve eqn1 = expr1 == 0; ... eqnn = exprn == 0; Then according to what you are trying to do you can proce...

4 years ago | 0

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Answered
Problem adding delay to dde23 model
lags = [1 0.2]; a = 5; tspan = [0 5]; sol = dde23(@(t,y,Z)ddefun(t,y,Z,a), lags, @history, tspan); plot(sol.x,sol.y(1,:),'-o...

4 years ago | 0

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Answered
How do I properly subtract two column vectors of class 'Double'
You calculate v = A*x - 1 in words: A*x - one instead of v = A*x - l in words: A*x - el

4 years ago | 1

Answered
How to efficiently delete rows from very large matrix
data(any(isnan(data),2),:) = [];

4 years ago | 0

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Answered
Is this how I find the area under my graph?
% ------ Finding time to climb to each altitude ------ % time_2_5_climb = trapz(final_list_2_5(:,6),final_list_2_5(:,8)) % 924...

4 years ago | 0

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Answered
How to find the coefficient matrix of a set of nonlinear equations?
There might be more elegant solutions, but this is one way you could generalize. I did it in octave ; maybe you will have to ac...

4 years ago | 1

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Unable to perform assignment because the left and right sides have a different number of elements
% Input Data Parameters h=1; % Step size [s] tf=50; % Solve Space of t=[0,tf] [s] ...

4 years ago | 1

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How to define a distance along a 2D nonlinear line generated by an equation, and find the corresponding distance along the x-axis?
syms x y = 5*0.12*(0.2969*sqrt(x)-0.1260*x-0.3516*x^2+0.2843*x^3-0.1015*x^4); f = sqrt(1+(diff(y,x))^2); f = matlabFunction(f...

4 years ago | 0

Answered
define matrix with variable to iterate over
function main ev = ...; hb = ...; w = (0:0.01:4)*ev/hb; D_= zeros(9,numel(w)); for n = 1:numel(w) M = Define...

4 years ago | 1

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Answered
error using sym/subindex
syms x f(x) = sqrt(1-x^3); V = pi* int(f^2,[0,1])

4 years ago | 0

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for loop does not plot all the plots
plot(24*i,y1(i*100e3),'*'); instead of plot(24*n,y1(n*100e3),'*');

4 years ago | 1

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How to make a solid of revolution using a function
https://de.mathworks.com/matlabcentral/fileexchange/15559-solids-of-revolution

4 years ago | 0

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Modeling Semiconductors using Poisson's Equation & PDE Equation Toolbox
If you have boundary conditions on both ends, use bvp4c. Else use one of the ODE solvers (e.g. ode45). Set y(1) = psi_i, y(2...

4 years ago | 0

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How to solve 2 non linear circle equations with vector inputs?
f(1)=(Cr^2)-((xx-Ch)^2)+((yy-Ck)^2); f(2)=(Gr^2)-((xx-Gh)^2)+((yy-Gk)^2); instead of f(1)=(Cr^2)==((xx-Ch)^2)+((yy-Ck)^2); f...

4 years ago | 0

Answered
Error when implementing Newton's method
i=1; x(i) =rand; y(i) =rand; f(i) = (1-x(i))^2 + 100*(y(i)-x(i)^2)^2; while f(i) > 1e-6 && i <20000 fx(i) = 2*x(i)-2+40...

4 years ago | 2

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Answered
Vector ODE solution is not periodic/ as expected
r = [2408.8; -6442.7;-0000.0]; v = [4.2908; 1.6052; 6.0795]; %rDot x = [r;v]; DU = norm(r); y0 = [r;v]; span = [0 20*pi]; ...

4 years ago | 0

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Matlab returns answer with another variable z. What does this mean?
Use SolUsb = solve(eqn, Usb, 'MaxDegree', 3) instead.

4 years ago | 0

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Use symbolic variable for lyapunov function
syms k_p k_d h A = sym('A', [3 3]); X = sym('X', [3 3]); A = [sym('0') sym('1') sym('0'); -k_p -k_d sym('0'); sym...

4 years ago | 0

Answered
Plotting of different nonlinear equations in different ranges segment wise in a single graph
x = 0:0.01:2; b = 0.3; c = 0.7; y = zeros(size(x)); idx = x>=0 & x<=0.3; y(idx) = 1 + sqrt(1+2*x(idx)); ...

4 years ago | 0

Answered
Warning: Matrix is singular, close to singular or badly scaled. Results may be inaccurate. RCOND = NaN. with Ode15s.
P0 = [0.5] %bar (Intial pressure) ...

4 years ago | 0

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Answered
Solving for a missing variable, I'm trying to solve for the value for Vc, but not sure how to write the code for it.
syms Vc eqn = ((100-Vc)/8)+7+((Vc-0)/6)==0 ; Vcnum = double(solve(eqn,Vc))

4 years ago | 1

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how to factor a analytic expression ?
F = factor(A) ; A = F(1)*F(2); does not work ?

4 years ago | 0

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'MY_ODE_WITHOUT_TLD returns a vector of length 2688, but the length of initial conditions vector is 2' why this error is showing?
The array dydt has 2688 elements (most probably because the vector ugdd has 2687 elements). The ode solver expects dydt of leng...

4 years ago | 1

Answered
How to solve a complicated algebraic equation with symbolic toolbox?
Either delta_w = k*pi (k integer) or delta_w = acos(((p1*e2)^2 + (p2*e1)^2 - (p1-p2)^2)/(2*p1*p2*e1*e2))

4 years ago | 1

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Answered
Trying to make a variable change between time intervals then output an array to plot the change of force
L=100; t=1:0.2:300; Mw = zeros(numel(t),1); Mw(t<100) = 20; Mw(t>=100 & t<=200)=100; Mw(t>200) = 17; F...

4 years ago | 0

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Answered
how to use loop in this equation
There are some mistakes in your article. The code is based on https://arxiv.org/pdf/2010.14993.pdf % Set parameters X0...

4 years ago | 0

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Answered
Plot not shown in for loop
iter = 0; for i=0:0.01:1 iter = iter + 1; I(iter) = i; if i<0.5 M(iter)=1 elseif i<0.7 M(iter)=0.5 ...

4 years ago | 0

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Answered
Plotting graph from non linear equation in MATLAB
A = 0:0.01:2; b = 1.577e11; c = 0.74; d = 1.9296e-7; R = 5e-9; x0 = -1.0; for i = 1:numel(A) a = A(i...

4 years ago | 1

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Answered
how to select last elements of a row vector?
j_last5 = j(end-4:end);

4 years ago | 1

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