Alan Stevens
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Answered
How to solve following BVP ODE?
Weird ODE and initial boundary condition! You can solve for small values of x using the following (where y(x=0) was chosen by t...
How to solve following BVP ODE?
Weird ODE and initial boundary condition! You can solve for small values of x using the following (where y(x=0) was chosen by t...
1 day ago | 1
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Answered
Array indexes must be positive integers or logical values.
Looks like you are using SUM when you want sum. Change to: SUM= E1*sum(V(3:IOUT+1,JOUT+2)).... Also, in line 59, you should h...
Array indexes must be positive integers or logical values.
Looks like you are using SUM when you want sum. Change to: SUM= E1*sum(V(3:IOUT+1,JOUT+2)).... Also, in line 59, you should h...
2 days ago | 1
| accepted
Answered
How to get real solutions of a "system of nonlinear equations"?
If you are willing to do the differentiation by hand then the following works % L = 2*x^2 -2*x*y+y^3 + lambda*(x^2 + y^2 -4); ...
How to get real solutions of a "system of nonlinear equations"?
If you are willing to do the differentiation by hand then the following works % L = 2*x^2 -2*x*y+y^3 + lambda*(x^2 + y^2 -4); ...
6 days ago | 0
Answered
Calling Euler Method to solve Shooting Method
You need to express your 2nd order ode as two 1st order odes y``(x) + 5y`(x) + 4y(x) = 1 v = dy/dx dv/dx = y``(x) So you h...
Calling Euler Method to solve Shooting Method
You need to express your 2nd order ode as two 1st order odes y``(x) + 5y`(x) + 4y(x) = 1 v = dy/dx dv/dx = y``(x) So you h...
6 days ago | 0
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Answered
solving Diffrential equation one parameter related to another one
Like this? %% Input Parameters Rs = 200; Rr = 180; Phi = 180; t = 0:1:359; e = Rs - Rr; %% Calculation B = @(t) e*co...
solving Diffrential equation one parameter related to another one
Like this? %% Input Parameters Rs = 200; Rr = 180; Phi = 180; t = 0:1:359; e = Rs - Rr; %% Calculation B = @(t) e*co...
6 days ago | 0
Answered
error handling for complex equation
nchoosek(pc-1+iL,pc-1-k) Your value of pc-1-k isn't a non-negative integer, but it needs to be for nchoosk. Also why use s...
error handling for complex equation
nchoosek(pc-1+iL,pc-1-k) Your value of pc-1-k isn't a non-negative integer, but it needs to be for nchoosk. Also why use s...
7 days ago | 0
Answered
merging two ode graphs
Your testode2 function must return a column vector. Try function dy = testode2(~,y) %%% Must return a column vector j=1;bet...
merging two ode graphs
Your testode2 function must return a column vector. Try function dy = testode2(~,y) %%% Must return a column vector j=1;bet...
7 days ago | 0
Answered
Simulation of differential equations with multiple variables. Biotechnology
You set umax to be 0.33, but then treat it as a function in the definition of f. If umax should simply be multiplied by the oth...
Simulation of differential equations with multiple variables. Biotechnology
You set umax to be 0.33, but then treat it as a function in the definition of f. If umax should simply be multiplied by the oth...
7 days ago | 0
| accepted
Answered
How can I keep on rejecting the value of input until the value inputted is greater than 0? Like how can they loop separately until the correct value is input?
Something like: dataX = -1; dataY = -1; while dataX<0 a=input('Please enter the X co-ordinate of the bottom left hand ...
How can I keep on rejecting the value of input until the value inputted is greater than 0? Like how can they loop separately until the correct value is input?
Something like: dataX = -1; dataY = -1; while dataX<0 a=input('Please enter the X co-ordinate of the bottom left hand ...
9 days ago | 0
| accepted
Answered
Solving system of simultanous ODE equations with Multiple Initial conditions
You could try something like: for i = 1:numel(CA0) [t, y]= ode15s(@kinatic3,tspan, [CA0(i) CB0(i) CC0(i)], option); f...
Solving system of simultanous ODE equations with Multiple Initial conditions
You could try something like: for i = 1:numel(CA0) [t, y]= ode15s(@kinatic3,tspan, [CA0(i) CB0(i) CC0(i)], option); f...
9 days ago | 0
| accepted
Answered
Solve an equation like the HP calculator solve
Use fzero. Replace the last line of your code with the following To2fn = @(To2) (1/alfa).*(((To2/p2).*sinh((A*p2)./(2.*To2)))./...
Solve an equation like the HP calculator solve
Use fzero. Replace the last line of your code with the following To2fn = @(To2) (1/alfa).*(((To2/p2).*sinh((A*p2)./(2.*To2)))./...
9 days ago | 0
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Answered
Finding and reporting the variable (Single number) of several with the largest value
Here's one possibility ABC = [0.0076, 0.46, 0.05]; abc = ['A','B','C']; greatestValue = abc(ABC==max(ABC))
Finding and reporting the variable (Single number) of several with the largest value
Here's one possibility ABC = [0.0076, 0.46, 0.05]; abc = ['A','B','C']; greatestValue = abc(ABC==max(ABC))
10 days ago | 0
Answered
Error while solving nonlinear differential equations using ode45
Then this line [t,y0]=ode45(@evapmodel,tspan,y0); should presumably be [t,y0]=ode45(@evapfunc,tspan,y0);
Error while solving nonlinear differential equations using ode45
Then this line [t,y0]=ode45(@evapmodel,tspan,y0); should presumably be [t,y0]=ode45(@evapfunc,tspan,y0);
10 days ago | 0
| accepted
Answered
Maxwell-Boltzmann Fit with different constant (air-absorption) for each data Point
You could try using fminsearch to estimate B. Something along the lines of: data = % enter your data to be fitted my = % ente...
Maxwell-Boltzmann Fit with different constant (air-absorption) for each data Point
You could try using fminsearch to estimate B. Something along the lines of: data = % enter your data to be fitted my = % ente...
11 days ago | 0
Answered
How can I solve the function numerically for changing Prandtl Numbers ? I couldn't handle this with a for loop inside of a function.
Like this? a = 0; b = 5; N = 1600; eta = (0:0.2:b); numberofeta=length(eta); A = zeros(numberofeta,6); %%%%%%%% B=ones(numb...
How can I solve the function numerically for changing Prandtl Numbers ? I couldn't handle this with a for loop inside of a function.
Like this? a = 0; b = 5; N = 1600; eta = (0:0.2:b); numberofeta=length(eta); A = zeros(numberofeta,6); %%%%%%%% B=ones(numb...
12 days ago | 0
| accepted
Answered
Plot all if condition with for loop
Do you mean like this: s = 0:0.1:1; for i=1:numel(s) if s(i) > 0 && s(i) <1 %avoid dividing by 0 Z2=sqrt((X.^2)+...
Plot all if condition with for loop
Do you mean like this: s = 0:0.1:1; for i=1:numel(s) if s(i) > 0 && s(i) <1 %avoid dividing by 0 Z2=sqrt((X.^2)+...
16 days ago | 0
| accepted
Answered
How do i solve this equation system?
Try fzero: d1 = 13; g = 9.81; d3 = d1/2; L2 = 72e3; L3 = 40e3; zb = 372; zc = 290; f1 = 0.02; c2 = 89; c3 = 45; w1 = ...
How do i solve this equation system?
Try fzero: d1 = 13; g = 9.81; d3 = d1/2; L2 = 72e3; L3 = 40e3; zb = 372; zc = 290; f1 = 0.02; c2 = 89; c3 = 45; w1 = ...
17 days ago | 0
Answered
Return function to go back to the beginning of the script
Make the euler routine a function and call it from a while loop. Along the lines of: ... while error>0.1 [h, error] = E...
Return function to go back to the beginning of the script
Make the euler routine a function and call it from a while loop. Along the lines of: ... while error>0.1 [h, error] = E...
17 days ago | 0
| accepted
Answered
Solve this using MATLAB
Replace F^2 in the first equation using the second equation. This will give you a fifth order polynomial in G. Use the roots f...
Solve this using MATLAB
Replace F^2 in the first equation using the second equation. This will give you a fifth order polynomial in G. Use the roots f...
18 days ago | 0
Answered
Improve Mathworks Euler method
The method is ok, though could be more streamlined, for example: f1=@(x) 5*x+50; f2 =@(x,y) x*10 +10*y; x1=0; y1=0; x2=0; ...
Improve Mathworks Euler method
The method is ok, though could be more streamlined, for example: f1=@(x) 5*x+50; f2 =@(x,y) x*10 +10*y; x1=0; y1=0; x2=0; ...
20 days ago | 0
Answered
How to solve the problem?
Like this? x=0:.1:2; y=0:.1:2; b=0.5;[X, Y]=meshgrid(x, y); uxy=zeros(size(X)); for a=1:2 m=a^2; pn=(16*m*sinh(pi*Y/2*a...
How to solve the problem?
Like this? x=0:.1:2; y=0:.1:2; b=0.5;[X, Y]=meshgrid(x, y); uxy=zeros(size(X)); for a=1:2 m=a^2; pn=(16*m*sinh(pi*Y/2*a...
20 days ago | 1
| accepted
Answered
Real solutions to polynomials
Try B = x^6 - x^4/5 + 14*x^2 - 2*x - 10 == 0; b = vpasolve(B,x) C = x^5 - 4*x^3 + 4*x^2 - (4*x)/3 - 10/3 == 0; c = vpasolve(...
Real solutions to polynomials
Try B = x^6 - x^4/5 + 14*x^2 - 2*x - 10 == 0; b = vpasolve(B,x) C = x^5 - 4*x^3 + 4*x^2 - (4*x)/3 - 10/3 == 0; c = vpasolve(...
21 days ago | 0
Answered
Error while performing integration
Like this: x=1:0.1:5; a=5; for i=1:length(x) z(i)=sqrt(a^2-x(i).^2); Q2(i)=quad(@(y) Zdirection(y,x(i),a),0,z(i)); %%%%%%%...
Error while performing integration
Like this: x=1:0.1:5; a=5; for i=1:length(x) z(i)=sqrt(a^2-x(i).^2); Q2(i)=quad(@(y) Zdirection(y,x(i),a),0,z(i)); %%%%%%%...
21 days ago | 0
| accepted
Answered
Use -> Basic fitting -> liner equation using code rather then the manual process
help polyfit help polyval
Use -> Basic fitting -> liner equation using code rather then the manual process
help polyfit help polyval
22 days ago | 0
Answered
how to Number the data points in the scatter plot – in increasing order of X
Here's one way: x=[2.6498, 5.4147, 7.7189, 7.9493, 7.2581, 47.5806, 44.1244, 78.4562, 73.3871, 74.3088, 91.8203, 96.659, 95.967...
how to Number the data points in the scatter plot – in increasing order of X
Here's one way: x=[2.6498, 5.4147, 7.7189, 7.9493, 7.2581, 47.5806, 44.1244, 78.4562, 73.3871, 74.3088, 91.8203, 96.659, 95.967...
24 days ago | 1
| accepted
Answered
How to change values for variables that are defined in a equation
More like this perhaps (of course you will need to use your on values for the constants): a = [75, 96.4]; b = [13.8, 14.1]; c...
How to change values for variables that are defined in a equation
More like this perhaps (of course you will need to use your on values for the constants): a = [75, 96.4]; b = [13.8, 14.1]; c...
26 days ago | 0
Answered
plotting is giving me multiple lines
A little more like this perhaps: %%%FIBER Ef=220e9;%[N/m] GPA to Newton/square meter Vf=.63; %fiber volume fraction vf=.33;%...
plotting is giving me multiple lines
A little more like this perhaps: %%%FIBER Ef=220e9;%[N/m] GPA to Newton/square meter Vf=.63; %fiber volume fraction vf=.33;%...
26 days ago | 0
Answered
I try to find the air under the curve of this signal
Like this? datacq= load('Acquisition.txt'); datacq(:,1)=datacq(:,1)-datacq(1,1); t=datacq(:,1)*10^-3; accelerationz=abs(data...
I try to find the air under the curve of this signal
Like this? datacq= load('Acquisition.txt'); datacq(:,1)=datacq(:,1)-datacq(1,1); t=datacq(:,1)*10^-3; accelerationz=abs(data...
27 days ago | 0
| accepted
Answered
ode45 second order
Matlab indices start at 1, so you want dy = [y(2); 3.6*sin(t) - 60*y(1) - 5*y(2)];
ode45 second order
Matlab indices start at 1, so you want dy = [y(2); 3.6*sin(t) - 60*y(1) - 5*y(2)];
27 days ago | 0
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