Answered

multiple equations multiple variables solve command does not work

These equations are linear in the unknowns, so can be solved as follows: % M*X = V where X = [b; d; e] % and the coefficien...

multiple equations multiple variables solve command does not work

These equations are linear in the unknowns, so can be solved as follows: % M*X = V where X = [b; d; e] % and the coefficien...

3 months ago | 1

Answered

Is there an error in the if else statement?

Yes, among others! See: L1 = 16.87; %cm L2 = 60.35; L3 = 16.81; L4 = 63.06; L5 = 42.62; L7 = 19.64; theta_1 = 105.47; %de...

Is there an error in the if else statement?

Yes, among others! See: L1 = 16.87; %cm L2 = 60.35; L3 = 16.81; L4 = 63.06; L5 = 42.62; L7 = 19.64; theta_1 = 105.47; %de...

3 months ago | 1

| accepted

Answered

Solving ODE Boundary Value Problem by Finite Difference Method

I think you just need to change b(i+1) = (w*xi(L-xi))/(2*E*I); to b(i+1) = (w*xi*(L-xi))/(2*E*I); ...

Solving ODE Boundary Value Problem by Finite Difference Method

I think you just need to change b(i+1) = (w*xi(L-xi))/(2*E*I); to b(i+1) = (w*xi*(L-xi))/(2*E*I); ...

3 months ago | 1

| accepted

Answered

Computing the double integral of a surface

Like this syms x y z = @(x,y) x.^2 + y.^2; surface_int = integral2(z,1,2,4,9); disp(surface_int)

Computing the double integral of a surface

Like this syms x y z = @(x,y) x.^2 + y.^2; surface_int = integral2(z,1,2,4,9); disp(surface_int)

3 months ago | 0

| accepted

Answered

Mod Euler Method with two ODEs

Like this %Mod_Euler_method Modified Euler's method % [t, w, h] = euler_method(f, a, b, alpha, n) performs Modified Euler's me...

Mod Euler Method with two ODEs

Like this %Mod_Euler_method Modified Euler's method % [t, w, h] = euler_method(f, a, b, alpha, n) performs Modified Euler's me...

3 months ago | 0

| accepted

Answered

im having trouble finding the right values for this codes

This should allow you to find the right values, though it might not be quite the way you were tasked to do it! %Initial Conditi...

im having trouble finding the right values for this codes

This should allow you to find the right values, though it might not be quite the way you were tasked to do it! %Initial Conditi...

3 months ago | 0

Answered

Break the for loop

Something like this perhaps: fib = [1; 1]; its = 0; keepgoing = true; while keepgoing its = its+1; r = rand; ...

Break the for loop

Something like this perhaps: fib = [1; 1]; its = 0; keepgoing = true; while keepgoing its = its+1; r = rand; ...

3 months ago | 0

Answered

How to take data on a column matrix (2661 x 1 double) for every 4 row then 3, sequently? So we take data only row 1, 5, 8, 12, 15, 19, 22, ... etc? Thank you.

Here's one way. There's probably a neater way. data=rand(1,2661); n = ceil(2661/3.5); ptr(1)=1; for i = 2:n ptr(i) = 4*(...

How to take data on a column matrix (2661 x 1 double) for every 4 row then 3, sequently? So we take data only row 1, 5, 8, 12, 15, 19, 22, ... etc? Thank you.

Here's one way. There's probably a neater way. data=rand(1,2661); n = ceil(2661/3.5); ptr(1)=1; for i = 2:n ptr(i) = 4*(...

3 months ago | 0

| accepted

Answered

Random draws from conditional multinomial distribution

Something like u = rand(1) if u<0.2 d = 0; elseif u<0.7 d = 2571; elseif u<0.9 d = 2571^2; else d = 25...

Random draws from conditional multinomial distribution

Something like u = rand(1) if u<0.2 d = 0; elseif u<0.7 d = 2571; elseif u<0.9 d = 2571^2; else d = 25...

3 months ago | 0

| accepted

Answered

How to define and plot a function with input range?

Like so: pt = @(t) (1 ./ (1 + t .^ 2)).*(t>=-0.5).*(t<=0.5); x = 0:0.01:10; y = 2*pt(x-1) + 4*pt(x-2) + 3*pt(x-3) + pt(x-4); ...

How to define and plot a function with input range?

Like so: pt = @(t) (1 ./ (1 + t .^ 2)).*(t>=-0.5).*(t<=0.5); x = 0:0.01:10; y = 2*pt(x-1) + 4*pt(x-2) + 3*pt(x-3) + pt(x-4); ...

3 months ago | 0

| accepted

Answered

Plot the slope of a parabola with only the data points being known

Like this? x = linspace(-0.5,0.5,25); %length in (meters) def_3mm_no_grav = -[0.00 5.82e-1 1.08 1.53 1.94 2.30 2.62 2.89 3.12 ...

Plot the slope of a parabola with only the data points being known

Like this? x = linspace(-0.5,0.5,25); %length in (meters) def_3mm_no_grav = -[0.00 5.82e-1 1.08 1.53 1.94 2.30 2.62 2.89 3.12 ...

3 months ago | 1

Answered

SIRE with vaccine model

Like this tspan = [0 1.5]; options = odeset('Refine', 10, 'RelTol', 1e-4); y0 = [5185000*0.3 5185000*0.7 1 1 0 0 0 0]; [t,...

SIRE with vaccine model

Like this tspan = [0 1.5]; options = odeset('Refine', 10, 'RelTol', 1e-4); y0 = [5185000*0.3 5185000*0.7 1 1 0 0 0 0]; [t,...

3 months ago | 1

| accepted

Answered

Problem with fplot function - displays grey zone instead of functions

Change all the ^ to .^ (i.e. dot^)and the * to .*

Problem with fplot function - displays grey zone instead of functions

Change all the ^ to .^ (i.e. dot^)and the * to .*

3 months ago | 1

Answered

I would like to create a handle function by for loop in matlab, but it does not work. I will be thankful if some body help me.

More like this? sfn = @(x,a,b) (a - b)*x; a=[1 2 3]; b=[4 5 6]; n=length(a); x = 1; % specify whatever x value you want f...

I would like to create a handle function by for loop in matlab, but it does not work. I will be thankful if some body help me.

More like this? sfn = @(x,a,b) (a - b)*x; a=[1 2 3]; b=[4 5 6]; n=length(a); x = 1; % specify whatever x value you want f...

3 months ago | 0

Answered

How to solve this implicit equation in matlab?

Good idea to plot a graph first, to see roughly where the root lies. Then use fzero. For example:: fn = @(x)log((0.77*x-0.77)...

How to solve this implicit equation in matlab?

Good idea to plot a graph first, to see roughly where the root lies. Then use fzero. For example:: fn = @(x)log((0.77*x-0.77)...

3 months ago | 0

Answered

Problem with solving discrete element method using leap frog method

The following gets the code working, but I've no idea if the results are meaningful!! n_part=4; kn=5; kt=2/7*kn; m=0.3; g=9...

Problem with solving discrete element method using leap frog method

The following gets the code working, but I've no idea if the results are meaningful!! n_part=4; kn=5; kt=2/7*kn; m=0.3; g=9...

3 months ago | 0

| accepted

Answered

Write a loop to plot a model graph

A little more like this. You need a smaller value of dv and a while loop. The fit isn't very good! %% Observed Wave dispersi...

Write a loop to plot a model graph

A little more like this. You need a smaller value of dv and a while loop. The fit isn't very good! %% Observed Wave dispersi...

3 months ago | 0

| accepted

Answered

Making a line thought points plotted from for loop in MATLAB

Like this? R1= 1399.580e+6; C1= 374.868e-6; R2= 1497.005e+6; C2= 350.472e-6; R3= 19573.407e+6; C3= 2429.373e-12;...

Making a line thought points plotted from for loop in MATLAB

Like this? R1= 1399.580e+6; C1= 374.868e-6; R2= 1497.005e+6; C2= 350.472e-6; R3= 19573.407e+6; C3= 2429.373e-12;...

3 months ago | 0

| accepted

Answered

How do I plot and return the values of multiple intersections between a function and zero?

Here's one possibility (though you get repeated results for the roots!): det_a = @(x) sin(x).*cosh(x) - cos(x).*sinh(x); x=0:1...

How do I plot and return the values of multiple intersections between a function and zero?

Here's one possibility (though you get repeated results for the roots!): det_a = @(x) sin(x).*cosh(x) - cos(x).*sinh(x); x=0:1...

3 months ago | 0

| accepted

Answered

Simplify Matrix decimal to integers

One way is M = [881/2158 985/1393 780/1351 881/2158 -985/1393 780/1351 -881/1079 ...

Simplify Matrix decimal to integers

One way is M = [881/2158 985/1393 780/1351 881/2158 -985/1393 780/1351 -881/1079 ...

3 months ago | 0

Answered

Tring to solve for a transcendental equation

You can rearrange the equation as eigen*tan(eigen) = Bi and use fzero as below. However, because of the nature of tan, your res...

Tring to solve for a transcendental equation

You can rearrange the equation as eigen*tan(eigen) = Bi and use fzero as below. However, because of the nature of tan, your res...

3 months ago | 0

| accepted

Answered

Question regarding MATLAB code to solve for electron in constant electric and magnetic field

If you are going to use global variables they need to be declared outside the function as well as inside. Your values of q and ...

Question regarding MATLAB code to solve for electron in constant electric and magnetic field

If you are going to use global variables they need to be declared outside the function as well as inside. Your values of q and ...

3 months ago | 0

Answered

Hello, I am trying to plot the transmission coefficient vs energy for the double barrier potential, but I get an error. May I know what I have done wrong here?

See the following V_0 = 0.2800; % Barrier strength in eV hbar = 1.054571596e-34; % Reduced Planck constant m = 5.465629128e-3...

Hello, I am trying to plot the transmission coefficient vs energy for the double barrier potential, but I get an error. May I know what I have done wrong here?

See the following V_0 = 0.2800; % Barrier strength in eV hbar = 1.054571596e-34; % Reduced Planck constant m = 5.465629128e-3...

3 months ago | 0

Answered

Simulation of point kinetics reactor equations

There are seven equations if you are using all six delayed neutron groups. You don't give your reactivity, nor the individual b...

Simulation of point kinetics reactor equations

There are seven equations if you are using all six delayed neutron groups. You don't give your reactivity, nor the individual b...

3 months ago | 1

| accepted

Answered

calculating angle between line of best fit and x axis

Take the arctangent of the gradient of the straight line.

calculating angle between line of best fit and x axis

Take the arctangent of the gradient of the straight line.

3 months ago | 0

Answered

deleting separate zeros from vector

Here's one way (there is probably a slicker way!): A = [ 0 0 1 0 0 0 1 0 1 0 0 1 5 9 8 2 0 3 0 1 0 0 0 ]; ...

deleting separate zeros from vector

Here's one way (there is probably a slicker way!): A = [ 0 0 1 0 0 0 1 0 1 0 0 1 5 9 8 2 0 3 0 1 0 0 0 ]; ...

4 months ago | 0

Answered

Making a Euler Method script to solve for velocity but am encountering "Array indices must be positive integers or logical values" Error

Try changing your loop to for i=1:numel(t) %%% i loop not t f = (g - (D * p * A * v(i).^2)/(2*m)); %%% v(i) v(i+1) ...

Making a Euler Method script to solve for velocity but am encountering "Array indices must be positive integers or logical values" Error

Try changing your loop to for i=1:numel(t) %%% i loop not t f = (g - (D * p * A * v(i).^2)/(2*m)); %%% v(i) v(i+1) ...

4 months ago | 0

Answered

Error solving for a particular variable from two equations

You could use fzero: TonTc = 0.01:0.01:0.99; a = zeros(1,numel(TonTc)); a0 = 1; % initial giuess for k = 1:numel(a) ...

Error solving for a particular variable from two equations

You could use fzero: TonTc = 0.01:0.01:0.99; a = zeros(1,numel(TonTc)); a0 = 1; % initial giuess for k = 1:numel(a) ...

4 months ago | 0

| accepted

Answered

Replacing sym with function handle

Do you mean something like this? phi = pi/3; [nr, wr] = fn(phi); disp(phi) disp(nr(4)+56*3/2) disp(wr(4)) function [nr...

Replacing sym with function handle

Do you mean something like this? phi = pi/3; [nr, wr] = fn(phi); disp(phi) disp(nr(4)+56*3/2) disp(wr(4)) function [nr...

4 months ago | 0

Answered

I'm trying to solve this system of ODE's describing a mechanical spring model.

Might be better to forget about symbolics, treat each 2nd order ode as two first order ode's and do the following: %applied for...

I'm trying to solve this system of ODE's describing a mechanical spring model.

Might be better to forget about symbolics, treat each 2nd order ode as two first order ode's and do the following: %applied for...

4 months ago | 0