Solve an equation not getting a result

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rita richa
rita richa on 12 Feb 2022
Commented: Star Strider on 12 Feb 2022
Hey here is my code, I don't know why I am not getting an answer,
E=9*10^3; nu=0.3; k=0.01; G=2*10^3; evide0=0.8;increment1=0.0001;
e1=[0:increment1:1];
s01=0;
s1=[s01];s1(1)=s01;
for i=2:length(e1)
syms x
a=double(solve(increment1==((1/3)*(k/(1+evide0))*((x-s1(i-1))/x))+((1/3*G)*(x-s1(i-1)))),x);
s1(i)=a
if s1(i)>500
s1=s1(1:(i-1));
break
end
end
I am not getting a value in a

Answers (2)

Catalytic
Catalytic on 12 Feb 2022
>> solve(increment1==((1/3)*(k/(1+evide0))*((x-s1(i-1))/x))+((1/3*G)*(x-s1(i-1))) ,x)
ans =
-2.6278e-06

Star Strider
Star Strider on 12 Feb 2022
The solve call was causing problems because the conversion and testing in the if block would then not work correctly because the logical test does not work for symbolic variables. Also, the ‘a’ result was frequently empty, and that effectively stopped the iteration. So I changed the call to fsolve (and made approprite changes to the code for the expression it was to solve) that elimnated those problems, and temporarily changed the value of ‘increment1’ to something reasonable that I could execute in the online Run feature here.
% syms x
E=9*10^3;
nu=0.3;
k=0.01;
G=2*10^3;
evide0=0.8;
increment1=0.0001;
increment1 = 0.01;
e1=[0:increment1:1];
s01=0;
% s1=[s01];
s1{1}=s01;
for i=2:length(e1)
% syms x
a = fsolve(@(x)increment1 - ((1/3)*k/(1+evide0)) * (x-s1{i-1})/x + ((1/3*G)*(x-s1{i-1})) ,(1+1i)*1000)
if isempty(a)
s1{i} = {0};
else
s1{i}=a;
end
if real(s1{i})>500
s1{i} = s1{1:(i-1)};
break
end
end
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.2222e-05 - 1.8158e-19i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.5762e-05 + 1.2116e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.9783e-05 + 3.8858e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.4050e-05 + 2.9737e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.8465e-05 + 2.2520e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.2979e-05 + 2.6854e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.7564e-05 + 2.3754e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.1220e-04 + 2.5388e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.2688e-04 + 2.6473e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.4159e-04 + 2.7222e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.5633e-04 + 2.7756e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.7109e-04 + 2.7273e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -1.8587e-04 + 2.7566e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.0066e-04 + 2.7299e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.1547e-04 + 2.7475e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.3029e-04 + 2.7318e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.4513e-04 + 2.7194e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.5997e-04 + 2.7286e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.7482e-04 + 2.7209e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -2.8968e-04 + 2.7272e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.0454e-04 + 2.7222e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.1941e-04 + 2.7180e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.3429e-04 + 2.7220e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.4917e-04 + 2.7192e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.6406e-04 + 2.7168e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.7895e-04 + 2.7194e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -3.9384e-04 + 2.7178e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.0874e-04 + 2.7164e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.2364e-04 + 2.7182e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.3855e-04 + 2.7198e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.5346e-04 + 2.7213e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.6837e-04 + 2.7226e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.8328e-04 + 2.7238e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -4.9820e-04 + 2.7233e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.1312e-04 + 2.7229e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.2804e-04 + 2.7238e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.4296e-04 + 2.7246e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.5789e-04 + 2.7244e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.7282e-04 + 2.7251e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -5.8775e-04 + 2.7249e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.0268e-04 + 2.7255e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.1761e-04 + 2.7261e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.3254e-04 + 2.7266e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.4748e-04 + 2.7271e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.6242e-04 + 2.7276e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.7736e-04 + 2.7275e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -6.9230e-04 + 2.7280e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.0724e-04 + 2.7283e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.2218e-04 + 2.7287e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.3712e-04 + 2.7290e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.5207e-04 + 2.7291e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.6701e-04 + 2.7291e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.8196e-04 + 2.7291e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -7.9691e-04 + 2.7294e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.1186e-04 + 2.7294e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.2681e-04 + 2.7294e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.4176e-04 + 2.7295e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.5671e-04 + 2.7297e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.7166e-04 + 2.7298e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -8.8662e-04 + 2.7300e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.0157e-04 + 2.7300e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.1652e-04 + 2.7302e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.3148e-04 + 2.7304e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.4644e-04 + 2.7306e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.6139e-04 + 2.7307e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.7635e-04 + 2.7309e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -9.9131e-04 + 2.7310e-14i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0010 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0010 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0010 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0011 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0012 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0013 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0013 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0013 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0013 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0013 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0013 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0014 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0015 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0015 + 0.0000i
Equation solved. fsolve completed because the vector of function values is near zero as measured by the value of the function tolerance, and the problem appears regular as measured by the gradient.
a = -0.0015 + 0.0000i
figure
plot(e1, real([s1{:}]))
grid
xlabel('e_1')
ylabel('s_1')
This runs without error. Make appropriate changes if it does not produce the desired result.
.
  2 Comments
Star Strider
Star Strider on 12 Feb 2022
My pleasure!
If my Answer helped you solve your problem, please Accept it!
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