MATLAB: Problem with command solve inside a function.

derivativefunctionMATLABsolveSymbolic Math Toolbox

Hi I have a problem using command solve in a function. My codes are:
function [a]=test(ka,landa)
sym x 
y = (ka/landa)*((x/landa)^(ka-1))* (2^(-(x/landa)^ka));
LO = diff(y);
sf=solve(LO,x);
tt=length(sf);
   if(tt>1)
      a= double(sf(2));
   end;
   if(tt ==1)
    a=double(sf(1));
   end;
  end
when I run this function with test(2.22,0.90), I get the answer 0.81 and tt=4, but when I call this function in another function I got 0 and the tt=1.
could you please help me with this? by the way I use MATLAB R2011a.
tanx
sasi

Best Answer

When I try running this function
function [a,tt] = runtest(ka,landa)
[a,tt] = test(ka,landa);
I get the same answer for both of the following commands:
[a,tt] = test(ka,landa)
[a,tt] = runtest(ka,landa)
(after fixing the top line of the function, which should be syms x).
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