Empty Sym when using vpasolve-operator.

e = [0.05:0.05:1];
syms tp
eqn = 900-e.*5.67*10^(-8)*tp^4-20*(tp-293)==0;
S = vpasolve(eqn,tp)

I get the following message: Empty Sym: 0-by-1 when running this. Any changes I can make?

Answer 1

[Torsten]

e = [0.05:0.05:1];
syms tp
for i=1:numel(e)
  eqn = 900-e(i)*5.67*10^(-8)*tp^4-20*(tp-293)==0;
  S{i} = vpasolve(eqn,tp);
end

[Iver Brekken]

Thank you! I want to plot S vs e (e at x-axis), and use the second element of every cell in S to do so. Any help?

[Torsten]

e = [0.05:0.05:1];
syms tp
for i=1:numel(e)
    eqn = 900-e(i)*5.67*10^(-8)*tp^4-20*(tp-293)==0;
    S(i) = double(vpasolve(eqn,tp));
end
plot(e,S)
end

Maybe you should use "roots" instead of "vpasolve" because your polynomial equation has 4 zeros.