solve an equation system with matlab
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    Alvaro Mª Zumalacarregui Delgado
 on 1 Mar 2021
  
    
    
    
    
    Commented: Alvaro Mª Zumalacarregui Delgado
 on 1 Mar 2021
            I trying to solve a system but when I run matlab send me an error, this is the code
syms a b
xo = 7000;
yo = 8000;
x  = 6600;
y  = 6500;
t  = 7;
eq1 = (b*xo-a*yo)/(exp(((b*xo-a*yo)*t)-((b*xo-a*yo)*(log(b*xo/yo)/(-(b*xo-a*yo)))))) == y;
eq2 = -(b*xo-a*yo)/(exp(((b*xo-a*yo)*t)-((b*xo-a*yo)*(log(-a*yo/xo)/(-(b*xo-a*yo))))))  == x;
solve([eq1 eq2], [a, b])
and the error
Warning: Unable to find explicit solution. For options, see help. 
> In sym/solve (line 317)
In sistema (line 16) 
ans = 
  struct with fields:
    a: [0×1 sym]
    b: [0×1 sym]
2 Comments
  Star Strider
      
      
 on 1 Mar 2021
				The two functions do not intersect, so they have no values of either ‘a’ or ‘b’ in common: 
syms a b
xo = 7000;
yo = 8000;
x  = 6600;
y  = 6500;
t  = 7;
eq1 = (b*xo-a*yo)/(exp(((b*xo-a*yo)*t)-((b*xo-a*yo)*(log(b*xo/yo)/(-(b*xo-a*yo)))))) == y;
eq2 = -(b*xo-a*yo)/(exp(((b*xo-a*yo)*t)-((b*xo-a*yo)*(log(-a*yo/xo)/(-(b*xo-a*yo))))))  == x;
eq1 = simplify(lhs(eq1)-rhs(eq1), 'Steps',500);
eq2 = simplify(lhs(eq2)-rhs(eq2), 'Steps',500);
figure
fsurf(eq1, [-1 1  -1 1]*1E+8)
hold on
fsurf(eq2, [-1 1  -1 1]*1E+8)
hold off
.
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