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Counting the number of increments in a vector
x = 0:0.1:7; numel(x(x<=3))

8 mesi fa | 0

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Get mean of a matrix which has NaN in it
grades = [2,4,6; 5, NaN, 1; 7, 2,NaN] mean(grades,1,"omitnan")

8 mesi fa | 0

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Resonance in moonpool type structures
I'd change k(n) = lsqnonlin(fun_alpha, guess, x0_left, x0_right); to k(n) = lsqnonlin(fun_alpha, guess, x0_left, x0_right,op...

8 mesi fa | 0

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Incorrect results for subtraction despite working for other use cases.
"segments_of_free_space" and "focal_lengths" (or "f" and "gaps") must have the same number of elements because you reference gap...

8 mesi fa | 0

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MATLAB Onramp: Help with Plots
The problem seems to be known: https://uk.mathworks.com/matlabcentral/answers/2178891-why-does-my-answer-to-a-task-show-up-as-i...

8 mesi fa | 0

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Help with Solving PDE System with DAE in MATLAB
You have discretized your equations in space. Thus the y variables are only functions of time for fixed z-coordinates. Here is...

8 mesi fa | 1

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Solving DE initial value problem symbolically in Matlab
By default, y is assumed a function of t: syms x y(t) sol(t) = dsolve('x*Dy+y=-sin(x)','y(pi/2)=0') simplify(x*diff(sol,t)+so...

8 mesi fa | 0

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How to iteratively solve when equations are dependent on each other.
Sigma_ysrtM = load("Sigma_ysrtM.mat").Sigma_ysrtM; T_oQlast = load("T_oQlast.mat").T_oQ; K_dot_nom = load("K_dot_nom.mat").K_d...

8 mesi fa | 0

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dispersion equation in water waves
I solve in y = x*h. Thus the result has to be divided by h to get x. k(j,n) = fzero(@(y)fun_alpha(y,omega(j)),y0_alpha)/h; The...

8 mesi fa | 0

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Difference between integral and cumtrapz.
Your input arguments to "cumtrapz" are reversed: you have to use intfx = cumtrapz(x,fx); instead of intfx = cumtrapz(fx,x); ...

8 mesi fa | 0

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Please 🙏 help me to find the exact solution of ODE
I doubt you can get an analytical expression for y. All you can do is to transform your 2nd order ODE into a system of first-ord...

8 mesi fa | 0

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Storing value in a matrix from a for loop.
Don't use "size" as a variable name - it's a MATLAB - reserved function: https://uk.mathworks.com/help/matlab/ref/double.size.h...

8 mesi fa | 0

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How to store a matrix so that I can call upon it in any other file I am working in?
Declare the matrix as "global" or pass it as input argument to all functions where it is needed. Or save it as a .mat-file and ...

8 mesi fa | 1

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Gaps in contour plot using custom secant method (when solving for two-plume merger)
The equation for rho is a polynomial of degree 4. The MATLAB function "roots" solves for the four zeros of this equation. I ...

8 mesi fa | 0

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May I ask everyone to help me solve this problem
I'm not sure, but if you want to integrate the normal distribution, use "mvncdf". integral2 can be very inaccurate when integrat...

8 mesi fa | 0

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Clustering using Gower's Distance
To use a distance that is not implemented, you have to define a function handle. Since I guess that GowerDst is not a function h...

8 mesi fa | 0

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Why do I get the wrong values for enthalpy on the P-h diagram block in Simulink/Simscape?
The reference enthalpy for R-134a is often given for the saturated liquid at -40°C, with a value of 148.4 kJ/kg. If you look at ...

8 mesi fa | 1

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Problems plotting an implicit solution to a differential equation
For more complicated cases where an explicit solution cannot be found: syms y(x) eqn = diff(y) == (2*x+y+2)/(2*x+y-4); soluti...

8 mesi fa | 0

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fft function seemingly not evaluating correctly
syms x f = 1/(2*sym(pi))*exp(-0.5*x^2); fourier(f) The Gaussian Pulse example under https://uk.mathworks.com/help/matlab/ref...

8 mesi fa | 0

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mvncdf seems to be violating the additive property of integrals
The complete IR^2 is made up of four quarter zones, not two. Sketch the quarter zones over which you integrate to understand wha...

8 mesi fa | 1

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how to evaluate the integral of the expression involving bessel functions.
l = 0; R_I = 2; N = 3; P = 3; k = [0.28,0.2,0.1,0.05]; %[k0,k1,k2,k3] e = [0.3,0.9,0.7]; %[e1,e2,e3] d = [0.1,0....

8 mesi fa | 0

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I have 9 coupled nonlinear ordinary differential equations. and i have to convert it in to state space form. here i have 9 state variable including theta.
Write your system as M(U,U')*U'' = f(U,U') with a (9x9) matrix M. Then you can use ode15s to solve the system V' = W ...

8 mesi fa | 0

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Solving boundary value problem
I think this is what you want. But although there are four boundary conditions for four free parameters, they do not suffice to...

8 mesi fa | 2

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Wierd wiggle in plot of symbolic expression
Using IB0(t) = vpaintegral(@(tau)B(tau,0),tau,0,t,'Waypoints',[1]); instead of IB0(t) = int(B(tau,0),tau,0,t); makes the wi...

8 mesi fa | 4

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How to Apply Multiple BC Types (Dirichlet, Robin, Neumann) on a Single 3D Face?
gd = [3 4 -0.5 0.5 0.5 -0.5 -0.5 -0.5 0.5 0.5; 3 4 0.5 1.5 1.5 0.5 -0.5 -0.5 0.5 0.5; 3 4 -1.5 -0.5 -0.5 -1.5 -0.5...

9 mesi fa | 1

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Risposto
Solving a system of a changing number of nonlinear equations
The solver doesn't converge. You should check parameters and equations. load 'AppxSteadyStateTestInput.mat' fun = @(x)test1(x,...

9 mesi fa | 0

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How to Apply Multiple BC Types (Dirichlet, Robin, Neumann) on a Single 3D Face?
Here is one way to create the geometry such that you can set different boundary conditions on different faces at the top. If yo...

9 mesi fa | 0

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Cap Maximum ODE solve time
Josh Meyer's answer shows you one possible way to do this: https://uk.mathworks.com/matlabcentral/answers/511547-possibility-to...

9 mesi fa | 1

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Please help me to plot surface figure. I want to draw this attached photo 2 dimension of (NG,etta) in 3 dimension as (NG, R,etta)
proj() function sol= proj clc;clf;clear; global n; global s %Relation of base fluid rhof=997.1*10^-3;kf=0.613*10^5;cpf=4...

9 mesi fa | 0

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Risposto
How do I delete specific parts of a graph
The arclength of a function will always be increasing. Thus your graph cannot be the arclength of a function. clear, clc syms ...

9 mesi fa | 1

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