Answered

How to solve 3 functions in 4 variables

What you show is NOT the answer. It is AN answer. 3 equations with 4 variables is called an underdetermined problem. There is ...

How to solve 3 functions in 4 variables

What you show is NOT the answer. It is AN answer. 3 equations with 4 variables is called an underdetermined problem. There is ...

environ 18 heures ago | 0

Answered

Error solving three equations in three unknowns

syms a b c Tan = -b - 2 == 0; Man = c + 1 == 0; Lan = a + b - 3*c - 1 == 0; [av,bv,cv] = solve(Tan,Man,Lan,a,b,c) This is a...

Error solving three equations in three unknowns

syms a b c Tan = -b - 2 == 0; Man = c + 1 == 0; Lan = a + b - 3*c - 1 == 0; [av,bv,cv] = solve(Tan,Man,Lan,a,b,c) This is a...

1 jour ago | 0

Answered

Numerical Approximation of Fisher Information Matrix

You cannot perform numerical differentiation? At the very least, you can use tools for numerical differentiation from my derives...

Numerical Approximation of Fisher Information Matrix

You cannot perform numerical differentiation? At the very least, you can use tools for numerical differentiation from my derives...

1 jour ago | 0

| accepted

Answered

Finding an analytical fit for a multi-dimensional function

Read again what Walter has said. There is much to learn for you. You might also look at some of what is found in this post, whi...

Finding an analytical fit for a multi-dimensional function

Read again what Walter has said. There is much to learn for you. You might also look at some of what is found in this post, whi...

2 jours ago | 0

Answered

optimization with multivariable and constraint

Sorry, but this seems just plain silly. You are way overthinking things. The new point P3 lies at the midpoint of the straight ...

optimization with multivariable and constraint

Sorry, but this seems just plain silly. You are way overthinking things. The new point P3 lies at the midpoint of the straight ...

2 jours ago | 0

Answered

How to create a 6 dimension array in Matlab and store values in it

It very much depends on what you want to do with that data. But I think you are looking for a very inefficient way to store your...

How to create a 6 dimension array in Matlab and store values in it

It very much depends on what you want to do with that data. But I think you are looking for a very inefficient way to store your...

2 jours ago | 0

Answered

How to write the codes for this gamma function?

Easy, peasy. Although since you are using gamma as a FUNCTION, it is a REALLY bad idea to use beta, another closely related spec...

How to write the codes for this gamma function?

Easy, peasy. Although since you are using gamma as a FUNCTION, it is a REALLY bad idea to use beta, another closely related spec...

3 jours ago | 0

| accepted

Answered

identify lowercase letters, uppercase letters, numbers and spaces

help ismember

identify lowercase letters, uppercase letters, numbers and spaces

help ismember

4 jours ago | 0

Answered

Recursive function to reverse a vector

Hmm. Suppose you strip off the last digit of the vector on each pass? Can you do that? You already know how to find the last ele...

Recursive function to reverse a vector

Hmm. Suppose you strip off the last digit of the vector on each pass? Can you do that? You already know how to find the last ele...

5 jours ago | 0

Answered

I want to make a recursive function that sums all the digits in a number

The "last" digit? A little ambiguously stated. In the number 12345, is 5 the last digit you are asking about? It looks like you...

I want to make a recursive function that sums all the digits in a number

The "last" digit? A little ambiguously stated. In the number 12345, is 5 the last digit you are asking about? It looks like you...

5 jours ago | 0

Answered

How can I interpolate a screw surface?

Is this a single valued function of x and y? Or x and z, y and z? No. Is this a function over some contiguous convex region in ...

How can I interpolate a screw surface?

Is this a single valued function of x and y? Or x and z, y and z? No. Is this a function over some contiguous convex region in ...

5 jours ago | 0

Answered

Help with syms function. Unable to find explicit solution

Would you assume that every equation you write down hs an analytical solution? Why would you? T = 10; h = 20; g = -9.81; ...

Help with syms function. Unable to find explicit solution

Would you assume that every equation you write down hs an analytical solution? Why would you? T = 10; h = 20; g = -9.81; ...

8 jours ago | 0

| accepted

Answered

how to separate variables of f(x,y)?

In a completely general sense, if you do not know IF the functions can be separated, then no it is probably impossible to do for...

how to separate variables of f(x,y)?

In a completely general sense, if you do not know IF the functions can be separated, then no it is probably impossible to do for...

9 jours ago | 1

Answered

nonlinear equality constraint with symbolic variables

Numerical optimizers CANNOT use symbolic variables. That is, this is meaningless when using a tool like fmincon. syms t [1 16...

nonlinear equality constraint with symbolic variables

Numerical optimizers CANNOT use symbolic variables. That is, this is meaningless when using a tool like fmincon. syms t [1 16...

9 jours ago | 0

Answered

linear regression in log-log scale

Sadly, while I wish the fitting tool would fit your data on log scales if that is how the axes are set, it does not. (That has a...

linear regression in log-log scale

Sadly, while I wish the fitting tool would fit your data on log scales if that is how the axes are set, it does not. (That has a...

10 jours ago | 0

Answered

Why multi objctive GA doesn't give identical answers?

First, many optimization problems have multiple solutions. Nonlinear problems often do. Second, there is no assurance that any ...

Why multi objctive GA doesn't give identical answers?

First, many optimization problems have multiple solutions. Nonlinear problems often do. Second, there is no assurance that any ...

10 jours ago | 1

| accepted

Answered

New to Matlab - need help with rearranging equation

There was NO error returned. It was a WARNING, that while you want to find a solution, none could be found. There are many thing...

New to Matlab - need help with rearranging equation

There was NO error returned. It was a WARNING, that while you want to find a solution, none could be found. There are many thing...

10 jours ago | 1

Answered

solve Equilibrium Position of Mass - Spring - Damped System

As Alan pointed out, you probably wanted to take the 2nd derivative of x there in your system, not the 20th derivative. The term...

solve Equilibrium Position of Mass - Spring - Damped System

As Alan pointed out, you probably wanted to take the 2nd derivative of x there in your system, not the 20th derivative. The term...

11 jours ago | 0

Answered

How do I express coefficient x, y, z using a, b, c, P0?

You can want to do anything you want. But unless you have a magic wand, that often fails. Here, you have ONE equation (3) that...

How do I express coefficient x, y, z using a, b, c, P0?

You can want to do anything you want. But unless you have a magic wand, that often fails. Here, you have ONE equation (3) that...

12 jours ago | 1

| accepted

Answered

How to solve Ax=B with some knowns in x and B

This is a moderately complex question, because I'm not sure you fully appreciate the problem, and I am also sure this is not you...

How to solve Ax=B with some knowns in x and B

This is a moderately complex question, because I'm not sure you fully appreciate the problem, and I am also sure this is not you...

13 jours ago | 0

Answered

Row of a Pascal's Triangle using recursion

Simplest is to use conv. In terms of your code, I have no idea what you think the line PascalRow(1) = 1; does, but it does not...

Row of a Pascal's Triangle using recursion

Simplest is to use conv. In terms of your code, I have no idea what you think the line PascalRow(1) = 1; does, but it does not...

16 jours ago | 0

Answered

memory overflow with double factorial function

Recursive formulas like this always seem useful, but they are terrible in terms of coding, in terms of efficiency. You don't wan...

memory overflow with double factorial function

Recursive formulas like this always seem useful, but they are terrible in terms of coding, in terms of efficiency. You don't wan...

17 jours ago | 0

| accepted

Answered

Unable to meet integration tolerances without reducing the step size below the smallest value allowed

Anytime you see this error message: "Unable to meet integration tolerances without reducing the step size below the smallest va...

Unable to meet integration tolerances without reducing the step size below the smallest value allowed

Anytime you see this error message: "Unable to meet integration tolerances without reducing the step size below the smallest va...

17 jours ago | 1

Answered

symbolic integration

No. You cannot first use a numerical integration to first integrate with respect to one variable, and THEN hope to use a symboli...

symbolic integration

No. You cannot first use a numerical integration to first integrate with respect to one variable, and THEN hope to use a symboli...

17 jours ago | 0

Answered

Need fast quadrature method for use within root-finding routine

Way too late for this answer to be useful. In fact, way too late even for it to have been useful for me, when I had to solve the...

Need fast quadrature method for use within root-finding routine

Way too late for this answer to be useful. In fact, way too late even for it to have been useful for me, when I had to solve the...

17 jours ago | 0

Answered

Constrain a parameter in a fit?

Simple enough. You could do this using lsqcurvefit or lsnonlin from the optimization toolbox, which do allow bound constraints o...

Constrain a parameter in a fit?

Simple enough. You could do this using lsqcurvefit or lsnonlin from the optimization toolbox, which do allow bound constraints o...

17 jours ago | 1

Answered

Why is lsqnonlin returning initial input values ?

lsqnonlin is not a function to optimize a scalar nonlinear function. Even though you could actually have written your problem in...

Why is lsqnonlin returning initial input values ?

lsqnonlin is not a function to optimize a scalar nonlinear function. Even though you could actually have written your problem in...

18 jours ago | 0

Answered

Solving Equation Generated by pchipinterp method

The simplest way to do this is to use my SLM toolbox. x = sort(rand(1,20)); y = rand(1,20); spl = pchip(x,y); fnplt(spl) y...

Solving Equation Generated by pchipinterp method

The simplest way to do this is to use my SLM toolbox. x = sort(rand(1,20)); y = rand(1,20); spl = pchip(x,y); fnplt(spl) y...

18 jours ago | 0

Answered

How to find the roots of the equraion f(x)=sin[sin(x)]+e^x=0

The simple answer is to know MATLAB syntax, and understand how to use a tool like fzero. So sin[sin(x)] may look better to you, ...

How to find the roots of the equraion f(x)=sin[sin(x)]+e^x=0

The simple answer is to know MATLAB syntax, and understand how to use a tool like fzero. So sin[sin(x)] may look better to you, ...

18 jours ago | 0

Answered

How to find unstable solution

Your question about how to get two lines in one graph is a simple one. Use the command "hold on" between plots. That is... plot...

How to find unstable solution

Your question about how to get two lines in one graph is a simple one. Use the command "hold on" between plots. That is... plot...

18 jours ago | 1