Error using / Matrix dimensions must agree...

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Below is my script:
>> clf
>> hold on
>> axis([-1 1 -1 1])
>> x=-1:0.0001:1;
>> y=cos(1/x)
>> plot(x,y)
May I know why I keep getting this error:-
(Error using / Matrix dimensions must agree...)?
  1 Comment
guadalupe presa
guadalupe presa on 22 Sep 2016
kEST=(s/(n+g+d))^(1/(1-alfa)); % realiza un código (k*)=steady state (NIVEL DE CAPITAL DE EQUILIBRIO)
SteadyState=findobj('Tag','STEADYSTATE'); set(SteadyState,'String',kEST);
upper=ceil(kEST)*2; jump=upper/10; k=(0:jump:upper)';
ec1=(n+g+d).*k; %ecuación 1= capital consumido: (n+g+d)*k (RECTA - FUNCION DE PRODUCCION) ec2=s.*k.^alfa; %ecuación 2= de capital acumulados:s*k^alfa (CURVA - FUNCION DE INVERSIÓN)
error: Error using / Matrix dimensions must agree.
Error in MODELOSOLOWCURVASFASE (line 87) kEST=(s/(n+g+d))^(1/(1-alfa)); % realiza un código (k*)=steady state (NIVEL DE CAPITAL DE EQUILIBRIO)

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Accepted Answer

Amit Nambiar
Amit Nambiar on 2 Oct 2013
It should be like this: >> clf >> hold on >> axis([-1 1 -1 1]) >> x=-1:0.0001:1; >> y=cos(1./x) >> plot(x,y)
always use .* ./ (mul and div resp)for element by element operations. And use * / without "." for matrix operations.

More Answers (6)

Matt J
Matt J on 2 Oct 2013
y=cos(1./x)

Image Analyst
Image Analyst on 2 Oct 2013

Mugisha Aime
Mugisha Aime on 21 Sep 2017
Matrix dimensions must agree.
  3 Comments
Muhammad Azrul Izmee
Muhammad Azrul Izmee on 27 Jan 2022
This is not right too.. I hv do it but keep getting error
Image Analyst
Image Analyst on 27 Jan 2022
@Muhammad Azrul Izmee, it is right. Here's proof
x=-1:0.0001:1;
y=cos(1 ./ x)
y = 1×20001
0.5403 0.5402 0.5401 0.5400 0.5400 0.5399 0.5398 0.5397 0.5396 0.5395 0.5395 0.5394 0.5393 0.5392 0.5391 0.5390 0.5390 0.5389 0.5388 0.5387 0.5386 0.5385 0.5384 0.5384 0.5383 0.5382 0.5381 0.5380 0.5379 0.5379
plot(x, y, 'b-')
See? No error.
You should start a new question with your own code.

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moahaimen talib
moahaimen talib on 20 Mar 2017
hi please i need your help i need to process many images into wavelet function
yFolder = 'images';
if ~isdir(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.jpg');
jpegFiles = dir(filePattern);
for k = 1:length(jpegFiles)
baseFileName = jpegFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
imageArray = imread(fullFileName);
figure(k);imshow(imageArray); % Display image.
drawnow; % Force display to update immediately.
[coeffa,coeffh,coeffv,coeffd]=wavelet_process(imageArray);
i recieve this error
Error using + Matrix dimensions must agree.
Error in idwt2 (line 89) x = upsconv2(a,{Lo_R,Lo_R},sx,dwtEXTM,shift)+ ... % Approximation.
Error in wavelet_inv_process (line 5) resimg=idwt2(coeffa,coeffh,coeffv,coeffd,'haar');
Error in top_run2 (line 74) inv_wave_img=wavelet_inv_process(coeffa,imgadjh,imgadjv,imgadjd);
please SOS

ahmed reda
ahmed reda on 3 Jul 2019
Edited: Image Analyst on 3 Jul 2019
i want to know the error of this code iwant to plot w with X&Y and this error is founed
clear ;
clc;
close all;
R=0.01; %Shaft radius
m=1.675; %Disc mass (Kg)
L=0.5; %Shaft Length (m)
E=210*10^9; %Modulus of elasticity (N/m^2)
Ro=7850; %Density (Kg/m^3)
Ix=(1/4)*pi*R^4; %Moment of Inertia (Kg.m^2)
A=pi*R^2; %Cross section area (m^2)
K=48*E*Ix/L^3; %Shaft Stiffness simply supported (N/m)
Z=0.00125; %Damping ratio
C=Z*2*sqrt(K*m); %Damping constant (N/m)
e=0.059665; %eccentricity (m)
N=1500; %(rpm)
w=(0:.5:30); %rotational speed (rad/sec)
Wn=sqrt(K/m); % natural frequency
% h=0.001; %time step (sec)
g=9.81;
O=m*g/K; %Initial deflection
T=5;fs=5*8*w/(2*pi); dt=1/fs; %sampling frequency
tspan=(0:dt:T); %time interval
% X0 = [0 0]; %Initial displacement, Initial velocity in X direction
% Y0 = [O 0]; %Initial displacement, Initial velocity in y direction
% [~,X]=ode45(@abdo,tspan,X0,[],m,K,C,w,e);
% [t,Y]=ode45(@reda,tspan,Y0,[],m,K,C,w,e);
X=(m*e*(w*w))/sqrt((K-m*(w*w))^2+(C*w)^2);
Y=(m*e*(w*w))/sqrt((K-m*(w*w))^2+(C*w)^2);
plot(w,X);grid;xlabel('W(rad/sec)');ylabel('X');
figure
plot(w,Y);grid;xlabel('W(rad/sec)');ylabel('Y');
The error is:
Error using /
Matrix dimensions must agree.
Error in amplitudewithfrequency (line 21)
T=5;fs=5*8*w/(2*pi); dt=1/fs; %sampling frequency
  5 Comments
Rafli Noorsyaif
Rafli Noorsyaif on 17 Jan 2021
clc
clear all
close all
%Diketahui (E1,E2,G12 dalam satuan MPa)
E = 180000;
SIGMAY = 502;
%S,A,W dalam satuan m
S = 0.1;
a = 0.005;
W = 0.01:0.01:0.1;
K = ((3*(S/W)*sqrt(a/W))/(2*(1+2*(a/W))*((1-(a/W))^(3/2))))*(1.99-(a/W)*(1-(a/W)))*(2.15-3.93*(a/W)+2.7*((a/W)^(2)))
Displacement = (K^(2))/(E*SIGMAY)
I have the same problem (Matrix dimensions must agree) on the line 14
K = ((3*(S/W)*sqrt(a/W))/(2*(1+2*(a/W))*((1-(a/W))^(3/2))))*(1.99-(a/W)*(1-(a/W)))*(2.15-3.93*(a/W)+2.7*((a/W)^(2)))
Image Analyst
Image Analyst on 17 Jan 2021
Rafli, usually what many/most people do in situations like this, which have an incredibly complicated and involved equation, is to break it down into smaller parts, then examine the size of each term. Like
term1 = 3*S/W;
term2 = sqrt(a/W);
and so on. Just basic debugging technique.
Then make sure all your matrix multiplication dimensionss of each term make sense, and also make sure you really want to do a matrix multiplication with star and not an element-by-element multipliication with dot star.For example since you have term1*term2, that means the number of columns in term1 must equal the number of rows in term1 for a matrix multiplication since term1 is on the left side.
Start your own question if you still have trouble.

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Rahayu A Halim
Rahayu A Halim on 8 Aug 2021
Hello, please I need your help
my script:
%____________________________________________________________________
function fx=obj_pid_ga(x)
global Kp Ki Kd
%
%
Kp=x(1);Ki=x(2);Kd=x(3);
%
%____________________________________________________________________
[t,~,y]=sim('model_sistem_PID',0:0.05:10);
%____________________________________________________________________
%Integral of Squared Error
fx=sum(t.*abs(y).^2);
May I know why I keep getting this error:
Error using .*
Matrix dimensions must agree.
Error in obj_pid_ga (line 10)
fx=sum(t.*abs(y).^2);

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