How to tell Solve function to only display real roots?

Question

lindsey Cameron 2014-11-27

评论： lindsey Cameron 2014-11-27

Hi guys,

Anyone know how I can restrict the Solve function in the current code to solve for only real values?

clear clc

syms x g

g=1.3099*10^15:0.05*10^15:2.6*10^15;

for i = 1:length(g) % Assigns i for each value within in g

      f=(((1.1096*10^17-(5.201*10^16)*(6.667*(x - 255)/x)^(1/3))/(g(1,i))) + 255-x);
      soln=solve(f,x);

end

Answer 1

Henrik 2014-11-27

I don't know if this is what you want, but you could do something like

real_soln=soln(imag(soln)==0);

or if there are floating point errors,

real_soln=soln(abs(imag(soln))<1e-9); %put appropriate tolerance here

lindsey Cameron 2014-11-27

Great, thanks it worked!