invalid use of operator

조회 수: 11 (최근 30일)
mohammad massarwe
mohammad massarwe 2021년 5월 3일
댓글: Walter Roberson 2022년 3월 27일
>>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)

답변 (2개)

James Tursa
James Tursa 2021년 5월 3일
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
  댓글 수: 8
mohammad massarwe
mohammad massarwe 2021년 5월 3일
File: untitled.m Line: 1 Column: 1
Invalid use of operator.
James Tursa
James Tursa 2021년 5월 3일
Get rid of the >> as Walter suggests.

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Abdul-Hamid Mohammed
Abdul-Hamid Mohammed 2022년 3월 27일
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.
  댓글 수: 4
Abdul-Hamid Mohammed
Abdul-Hamid Mohammed 2022년 3월 27일
% 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 2022년 3월 27일
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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