I have a MSc in physics from the University of Oslo and a PhD in control engineering from NTNU in Trondheim (mainly modelling, I am not much of a control engineer). My main interests are mathematical modelling, numerical methods, and thermodynamics. I worked in the petroleum and chemical process industries for some 35 years and I am now semi-retired

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Problem relating to mathematical expression

Ameer's answer is correct, of course. Here is another approach, without the elegant Matlab functions: N = 5; % Max window size...

Problem relating to mathematical expression

Ameer's answer is correct, of course. Here is another approach, without the elegant Matlab functions: N = 5; % Max window size...

14 hours ago | 0

Answered

Help text does not work for user-defined functions

Problem solved - finally! My Matlab 2019b and 2020a installations had several other odd behaviours in addition to the help prob...

Help text does not work for user-defined functions

Problem solved - finally! My Matlab 2019b and 2020a installations had several other odd behaviours in addition to the help prob...

3 days ago | 1

Answered

Solution for system of two non linear equation

You can rewrite you equations as (Nd-x-y)-a*(x*(x+y)) = 0 (Nd-x-y)*(No-y)-b*(y*(x-y)) = 0 where x = Nd, y = Nonegative, a = ...

Solution for system of two non linear equation

You can rewrite you equations as (Nd-x-y)-a*(x*(x+y)) = 0 (Nd-x-y)*(No-y)-b*(y*(x-y)) = 0 where x = Nd, y = Nonegative, a = ...

5 days ago | 1

| accepted

Answered

Problem of erf when using fmincon

Your problem has infinitely many solutions. Whenver x(1)-x(3) = 1 and x(2)-x(4) = 1, fun = 0, which is the minimum value possib...

Problem of erf when using fmincon

Your problem has infinitely many solutions. Whenver x(1)-x(3) = 1 and x(2)-x(4) = 1, fun = 0, which is the minimum value possib...

14 days ago | 0

Answered

how to Nonlinear equations?(two variables)

Although R1 and R2 are nonlinear finctions of t, your equations are linear in x. So you write the equations on the form A(t)*...

how to Nonlinear equations?(two variables)

Although R1 and R2 are nonlinear finctions of t, your equations are linear in x. So you write the equations on the form A(t)*...

27 days ago | 2

| accepted

Answered

How to count number of times a number appears in column B based on column A

letters = 'ABAACD'; numbers = [1,2,2,1,1,3]; uniqueletters = unique(letters); uniquenumbers = unique(numbers); n = length(un...

How to count number of times a number appears in column B based on column A

letters = 'ABAACD'; numbers = [1,2,2,1,1,3]; uniqueletters = unique(letters); uniquenumbers = unique(numbers); n = length(un...

29 days ago | 0

| accepted

Submitted

nistdata(species,T,p)

Create tables of thermophysical properties for gases

2 months ago | 19 downloads |

Answered

Van der Waals equation - Newton's method

In your code, newton_ndim does not know the value of T and so cannot call fun(X,T). You can probably fix this by defining an in...

Van der Waals equation - Newton's method

In your code, newton_ndim does not know the value of T and so cannot call fun(X,T). You can probably fix this by defining an in...

2 months ago | 0

| accepted

Submitted

Curvature of a 2D or 3D curve

Calculates the local radius of curvature as well as the cumulative arc length and the curvature vector along a 1D curve in 2D or...

2 months ago | 107 downloads |

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How Far Can You Throw Something?

As you probably learned in your high school physics class, throwing an object at a 45 degree angle will give you the maximum ran...

3 months ago

Solved

Calculate the height of an object dropped from the sky

Assume that an object is dropped from 1000 meters above the surface of the earth at time t=0. The object is dropped such that t...

3 months ago

Solved

Distance of the centroids of the balls

Given *n* balls of radius *r* and the vector *p (nx3)* with all position *(x,y,z)* of the balls, return the symmetric matrix *A ...

3 months ago

Solved

Calculate compression ratio of engine

Calculate compression ratio of engine given compression volume of cylinder(Vc), piston stroke(s) and valve diameter(d)

3 months ago

Solved

Elastic Collision 001: 1-D

Elastic Collision of two particles. <http://en.wikipedia.org/wiki/Elastic_collision wiki Elastic Collision> Solve Conservat...

3 months ago

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Center of mass

Given a matrix M(m,n), where m is the number of vertices of the geometrical element and n is 2 or 3 (2D-plane figure or 3D-solid...

3 months ago

Solved

center of mass

R is a given matrix with size [n,2]. R(i,:) is interpreted as the 2D-position of a mass point with mass i. Calculate the center ...

3 months ago

Solved

Determine if a four bar mechanism is of Grashof type

A four bar mechanism is composed of four links. if s is the smallest link, l the longest and p,q are the length of the other lin...

3 months ago

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Find the jerk

No, it's not the author of this problem... Jerk is the rate of change in acceleration over time of an object. So, if given t...

3 months ago

Solved

Juggling

There is a notation system for <http://en.wikipedia.org/wiki/Juggling jugglers> called <http://en.wikipedia.org/wiki/Siteswap si...

3 months ago

Solved

Bernoulli's Equation

Bernoulli's equation states that for an incompressible fluid the following summation is constant across the flow: v^2/2 + g*z + ...

3 months ago

Solved

What gear ratio does the cyclist need?

A cyclist (perhaps including our famed Codysolver the cyclist <http://www.mathworks.com/matlabcentral/cody/players/1841757-the...

3 months ago

Solved

Mechanical Advantage of a Gear Train

Calculate the mechanical advantage of a gear train. The mechanical advantage of a gear couple is given by MA = T_o/T_i where ...

3 months ago

Solved

Kepler's Equation

Solve <http://en.wikipedia.org/wiki/Kepler's_equation Kepler's Equation>. Note that the solution is rounded down to 5 decima...

3 months ago

Solved

Energy of an object

Calculate the total mechanical energy of an object. Total Energy= Potential energy + Kinetic energy P.E.=m*g*h K.E.=1/2...

3 months ago

Solved

Bouncing disk

A disk is placed in a rectangular room with dimensions a and b in a point with coordinates x0 and y0. The disk is given a startu...

3 months ago

Solved

jogging?

Imagine x-y coordinate system and you are at the origin and your partner is on the x-axis at some small distance (d) away from y...

3 months ago

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How do I solve system of equations?

If I understand you correctly, your system consist of 128 eqations. a and b are arrays of 64 unknowns each. You must then solv...

How do I solve system of equations?

If I understand you correctly, your system consist of 128 eqations. a and b are arrays of 64 unknowns each. You must then solv...

3 months ago | 0

| accepted

Answered

Join repeated continuous elements of a vector

in = [1 1 1 2 2 3 6 6 6 1 1 1 4 4 4 2 2 2 6 4 4]; i = 1; count = 1; out = []; a = in(1); while i < length(in) i = i+1; ...

Join repeated continuous elements of a vector

in = [1 1 1 2 2 3 6 6 6 1 1 1 4 4 4 2 2 2 6 4 4]; i = 1; count = 1; out = []; a = in(1); while i < length(in) i = i+1; ...

3 months ago | 0

Submitted

Thermo: Compressible real gas tool

A Matlab object for calculating consistent thermodynamic properties of real gases

3 months ago | 7 downloads |

Solved

Mechanics 1

I thought I would make a mechanics problem for all those physics lovers out there. Imagine two solid, rigid spheres B1 and B...

3 months ago