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**Feeds**

problem doing implicit plotting

Remove the dot at the end of the expression x.*y.

5 hours ago | 1

Why i am getting blank graph? Can someone help me to figure out error in my code.

is_exam3() function is_exam3 L=0.01; M=0; q=0.5; a=0.03; Pr=0.1; b=0.2; p=0.1; m=0.1; e=1.0; H=0.1; E=0.1; o=0...

9 hours ago | 0

How to solve the following PDE equation

I think you mean x(s,0) = 10 instead of x(s,t) = 10, don't you ? The easiest way to solve the equation is to discretize the exp...

10 hours ago | 0

| accepted

Matrix is singular to working precision.

Obviously, your matrix is the zero matrix. Most probably the reason is that you don't assign values to K in the loop K(2*cnt-1...

1 day ago | 0

Solving unknown matrics to the power 20

p = [1 0 0 0 0 0 0]; R = [9; 8; 7; 6; 5; 4; 3]; CR = [0.45]; n = 20; TPM = diag([(CR/(p(1)*R(1)))^(1/n),zeros(1,6)]); p*TPM...

2 days ago | 0

Error using pdepe: Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative

"pdepe" is a solver for parabolic-elliptic equations. Thus all equations should have a second-order derivative term in space and...

2 days ago | 0

| accepted

In matlab, although my matrix is full rank, the solution is still incorrect.Ax=b,A(10000*10000),x、b(10000*1)

The condition number of your matrix D is around 1e11 (see above). This is near to singular. I think you cannot expect a better r...

2 days ago | 1

Too many input arguments error

Your function xa and xn have three inputs (n,x,g), not two (n,g). Thus x_func = @(n, g) (xa(n, g)/xn(n, g))^(1/3); % Example T...

2 days ago | 0

solving symbolic equations with partial derivatives

syms Cf(zf,zr) cf(z,theta) L zref = zf; thetaref = (zf - zr)/L; dCfdzf = diff(cf,z) * diff(zref,zf) + diff(cf,theta)*diff(the...

2 days ago | 0

Calculations with distributions of variables only

Look up "Monte-Carlo-Simulation".

3 days ago | 0

Time-dependent dynamic problem with nonlinear stiffness using ode45

You solve for U and Udot - thus you get values for U and Udot from ode45. Simply compute the matrix K(U) with these values and p...

4 days ago | 0

Error: Data must be numeric, datetime, duration, categorical, or an array convertible to double.

% Declaring Theta and Phi Variables theta = 0:0.1:pi/2; % Phi Values phi_E_Plane = 0; phi_H_Plane = pi/2; % Declaring x...

5 days ago | 0

How to solve this differential equation? I got ''Warning: Unable to find symbolic solution.'' error. What am I missing ?

You don't miss anything - your equation is just too complicated to have an analytical solution. You will have to use a numerica...

6 days ago | 0

| accepted

fsolve error: Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

Include the line size((2.*x_SW(2).*dfreq_SW_vr.*w(1).*g2) + ((1./4).*x_SW(1).*nu).*(f1b.*zet_0_0 + f2b.*eta_0_0).*g1.*cos(gamm...

6 days ago | 0

Hi All. Just wondering why answer to (i) is not 4.9e+4. an why answer to (iii) is not (9x)/2 or 4.5 x. Many thanks. Brian

For (iii), use syms x real instead of syms x

7 days ago | 1

Overwriting the maximum function evaluation

You didn't include the structure "optim_lsq" in the call to lsqcurvefit.

8 days ago | 0

How do you compute the product of a matrix and each column of another matrix without a for loop in MATLAB, or is this just not possible?

y = C*x

8 days ago | 0

| accepted

Operands to the logical AND (&&) and OR (||) operators must be convertible to logical scalar values. Use the ANY or ALL functions to reduce operands to logical scalar values.

if all(abs(grad_g1_val) < tol) && subs(g1, {x1, x2, x3}, x') <= 0 activeSet = [activeSet, 1]; % Constraint 1 is ac...

8 days ago | 0

| accepted

ODE45 and dsolve result difference

dydx(2)=2-2*y(2)-8*x; instead of dydx(2)=2-2*y(2)-8*y(1);

8 days ago | 1

| accepted

Intersection condition between two ellipses

I'm surprised that we get a division by zero by the below solution method if the aspect ratio of the two ellipses is equal. Bu...

8 days ago | 0

Arrayfun with Extra Parameters

Test3 = arrayfun(f,a,b) instead of Test3 = arrayfun(@f,a,b)

9 days ago | 0

| accepted

Extract the indices based on the minimum absolute value

Maybe you mean %define the number of random numbers n = 10; %define the min and max ranges of random values stvar = [0 4]...

9 days ago | 0

How to fit a distribution whose parameters depend on other parameters?

In this case, you must assume a parametric expression for T(z) as well (e.g. T(z) = a + b*z) and add a and b to the parameters t...

9 days ago | 0

Solve and plot system in x and y with varying constants e and t

basically i would like to obtain on the same graph different curves in x and y for a fixed number of combinations of e and t. I...

11 days ago | 0

| accepted

sol2 = bvp4c(@bvpexam2, @bcexam2, sol);

Ibrardual() function Ibrardual Nt=0.5; Nb=0.5; Le=2; Pr=1; Alpha=[-0.2138;-0.4]; s=1; A=1; %% solution in structure form %...

11 days ago | 0

| accepted

What is the most computationally efficient factorization of a matrix A?

Prove that the matrix is positive definite and count the number of FLOPs of Cholesky compared to the other factorizations. Sect...

12 days ago | 0

what is the error here?

The error is that the parameter "S" is not an input to function "odeBVP" and thus undefined in f =[y(2);y(3);(1/3)*D1*((y(2)^2...

13 days ago | 0

Runge kutta giving complex numbers

It doesn't make sense to use such discontinuous input data for the solution of a differential equation. Solving a differential ...

15 days ago | 0

How does Matlabs Symbolic Math Toolbox always finds an analytical eigendecomposition for arbitrary polynomial matrices?

For me this begs the question, is the eigenvalue polynomial from eig(...) truly analytic? What do you mean for a polynomial to ...

15 days ago | 1

| accepted

Want to understand how to implement in matlab the following differential equation?

If you know P1 over time, you don't have a differential equation, but simply an algebraic relation to determine Q: Q = (P1-P2)/...

15 days ago | 0