invalid use of operator

11 vues (au cours des 30 derniers jours)
mohammad massarwe
mohammad massarwe le 3 Mai 2021
Commenté : Walter Roberson le 27 Mar 2022
>>shitathatsia = @(x) 2.7*cos(25*x^2+8*x)-10*x*sin(6*x)
starrt=-1
ennd=1
pitaron= (starrt+ennd)/2
while sqrt((shitathatsia(pitaron))^2)> 0.001
if(shitathatsia(pitaron)) * shitathatsia(start) <0
starrt = pitaron
if shitathatsia(pitaron)) * shitathatsia(start) >0
ennd=pitaron
end
pitaron=(starrt+ennd)/2
end
fprintf(pitaron)

Réponses (2)

James Tursa
James Tursa le 3 Mai 2021
You are missing a ( after the second "if", and you are missing an "end" statement. That being said, my suggestion would be to use an "else" instead as that appears to be your intent. E.g.,
if ( condition )
starrt = pitaron;
else
ennd = pitaron;
end
  8 commentaires
mohammad massarwe
mohammad massarwe le 3 Mai 2021
File: untitled.m Line: 1 Column: 1
Invalid use of operator.
James Tursa
James Tursa le 3 Mai 2021
Get rid of the >> as Walter suggests.

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Abdul-Hamid Mohammed
Abdul-Hamid Mohammed le 27 Mar 2022
for i=1:length(t)-1
x(i+1)=x(i)+(a*(x^2)(i)*(1+B(x^2)(i)-q*x(i)*E(i)))*Dt;
E(i+1)=E(i)+(z*(p*q*x(i)*E(i)-c*E(i)))*Dt;
end;
I am getting invalid use of operator with the above syntex, pls how do i resolve it. thank you.
  4 commentaires
Abdul-Hamid Mohammed
Abdul-Hamid Mohammed le 27 Mar 2022
% Euler's Method
% Initial conditions and setup
% x(t+1)=x(t)+(a*(x(t)^2)*(1+B(x(t)^2)-q*x(t)*E(t)))*Dt
% E(t+1)=E(t)+(z*(p*q*x(t)*E(t)-c*E(t)))*Dt
%
%=======================================================================
a=1; alpha value
B=25; beta value
q=0.1; %catchability
z=0.1; %effort
p=100; %price
c=4; %cost
Dt=0.01; %delta t
timesteps=50;
t=0.1:Dt:timesteps; %array with time
for i=1:length(t)-1
x(i+1)=x(i)+(a*(x(i)^2)*(1+B(x(i)^2)-q*x(i)*E(i)))*Dt;
E(i+1)=E(i)+(z*(p*q*x(i)*E(i)-c*E(i)))*Dt;
end;
Walter Roberson
Walter Roberson le 27 Mar 2022
B(x(i)^2) is a request to index your scalar value B at the location determined by the calculation. Perhaps you forgot a multiplication.

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