problem using command solve?!

Hi

I have a problem using command solve. when I write these commands on the command window, I get 4 answers for m equation.

ka=2;
landa=4;
syms x
y = (ka/landa)*((x/landa)^(ka-1))* (2^(-(x/landa)^ka));
LO = diff(y);
sf=solve(LO,x)

but when i use these same codes in my m.file I have get errors regarding mupad. Moreover I can access to the first answer of sf, not all of them.

Does anybody why this happen?

tnx

sasi

Answer 1

[Friedrich]

Hi,

when I run your code from the command window I get two solutions:

ka=2;
landa=4;
syms x
y = (ka/landa)*((x/landa)^(ka-1))* (2^(-(x/landa)^ka));
LO = diff(y);
sf=solve(LO,x)

sf =

    (2*2^(1/2))/log(2)^(1/2)
   -(2*2^(1/2))/log(2)^(1/2)

Running it in a script or functions works fine too. What error do you get? Which version of MATLAB are you using?

[Sasi]

Hi,

yes you are right. I am so sorry.

if you run it again with:

ka=2.22;

landa=0.90;

then you will get 4 answers.

But I dont get all the answers when I use them in function. I use MATLAB R2011a.

Thank you very much

[Sasi]

Oh I find my mistake, tanx Friedrich. ;)