Why is my integration in Mathematica not working?

[aminbkh]

Hi,
I have a question about fitting in Mathematica.I have a function like this:
F=T*Y^(0.5) T is temperature but Y obtained from this coupled equation 1-u*Y=u(1-u/Y^.4)^.5*Y
I have T and F from experimental data.so I want to obtain u from fitting.
could you please advise me how can I do it by Mathematica.
Thank you

 

[aminbkh]

Question about matlab

Hi,
I have question if you could answer me, I really appreciate it. I have an equation which I wan to solve it to experimental data \[Rho] = t*Y^.5*a + Y^.8/sqrt (1 + 4*Y)*t*a^2 where a is parameter which I want to obtain by fitting and t is vector that I know for each experiment. and Y obey this equation 1 - (1 - u)*Y = u*(1 + g/t*y^.5)^.5*Y^.43 where u and g are again system Dependant parameter which should be obtained by fitting it means that in each iteration first that coupled equation should be solved with respect to Y and put in rho equation to obtain u,g and a do you know if MATLAB is able to do that or not?or ant other suggestion I really appreciate your help

 

[es1]

The mathematica FindFit function will do this for you.
http://reference.wolfram.com/mathematica/ref/FindFit.html

 

[aminbkh]

thank you for your answer
but the problem is the function Y should be solved and then put in second equation and both of them have some adujstable parameters,
could you advise me more please.

 

[aminbkh]

Hi all,
I have this integration in mathematica but I don't know why doest work.
Could you please help me?

Integrate[HeavisideTheta[0.1 - x], {x, 0, 100}]

Thank you so much for your help

 

[phyzguy]

Hi all,
I have this integration in mathematica but I don't know why doest work.
Could you please help me?

Integrate[HeavisideTheta[0.1 - x], {x, 0, 100}]

Thank you so much for your help

It works when I do it. See the attached notebook. Did you mis-type it?

Edit: Oops, I see what you mean. The answer should be 0.1, not 100.0. Looks like a bug. It plots the Heviside function correctly, but appears not to integrate it correctly. Hmmm.