How can I simplify the symbolic expressions?
    9 views (last 30 days)
  
       Show older comments
    
    Ali Almakhmari
 on 11 Sep 2023
  
    
    
    
    
    Edited: Ali Almakhmari
 on 11 Sep 2023
            I hate the fact that solve keeps outputting symbolic expressions with extremely large numbers, when clearly it can simplify further and get rid of those numbers. How can I force it to do that? Its okay with me if I can get an approximation up 6 decimal places.
clear
clc
syms q_bar delta_o theta1 theta2 q S CL_alpha CL_delta b e KT
eqn1 = (2*theta1 - theta2 - q_bar.*theta1 + q_bar.*theta2) == (-0.4805020381.*q_bar.*delta_o);
eqn2 = (-theta1 + theta2 - 2.*q_bar.*theta2) == (-0.0051005137.*q_bar.*delta_o);
sol = solve(eqn1,eqn2,theta1,theta2);
L1 = q.*S.*CL_alpha.*sol.theta1;
L2 = q.*S.*CL_alpha.*sol.theta2 + q.*S.*CL_delta.*delta_o;
eqn1 = (0.25.*L1.*b + 0.75.*L2.*b) == 0;
a=solve(eqn1,q_bar)
1 Comment
  Torsten
      
      
 on 11 Sep 2023
				If you need 6 decimal places, why do you supply model parameters with 10 decimal places ?
-0.4805020381*q_bar
-0.0051005137*q_bar
Accepted Answer
  John D'Errico
      
      
 on 11 Sep 2023
        
      Edited: John D'Errico
      
      
 on 11 Sep 2023
  
      clear
clc
syms q_bar delta_o theta1 theta2 q S CL_alpha CL_delta b e KT
eqn1 = (2*theta1 - theta2 - q_bar.*theta1 + q_bar.*theta2) == (-0.4805020381.*q_bar.*delta_o);
eqn2 = (-theta1 + theta2 - 2.*q_bar.*theta2) == (-0.0051005137.*q_bar.*delta_o);
sol = solve(eqn1,eqn2,theta1,theta2);
L1 = q.*S.*CL_alpha.*sol.theta1;
L2 = q.*S.*CL_alpha.*sol.theta2 + q.*S.*CL_delta.*delta_o;
eqn1 = (0.25.*L1.*b + 0.75.*L2.*b) == 0;
a=solve(eqn1,q_bar)
They are simple already. At least, as simple as they can be. You have unknowns in there, inside and outside of the square roots. I suppose you could play around, and make it different, but simpify will not find anything glaring to reduce there.
Can you make the numbers smaller? Well, yes, you can force VPA to round them.
vpa(a,10)
Is that simpler? I guess.
More Answers (0)
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!




