Hi,

i need to solve the diff the funktion q.total(t.0) to find its maximum value. It alsways says t.0 not defined. What do I do wrong? Pls help.



Fin-Heatexchanger.sm (28,84 KiB) scaricato 1502 volta(e).

Direct answers to questions are more beneficial than no-meaning replies.
You don't need to ignore units, if possible never do that.
If unit ignore suggestion comes from Jean, especially ignore it.
He is notorious being wrong with engineering problems.
If it comes from {mkraska, Razonar, uni, etc} you can take it serious.

Regards

Fin-Heatexchanger_solved.sm (36,13 KiB) scaricato 1481 volta(e).

Wrote

Direct answers to questions are more beneficial than no-meaning replies.
You don't need to ignore units, if possible never do that.
If unit ignore suggestion comes from Jean, especially ignore it.
He is notorious being wrong with engineering problems.
If it comes from {mkraska, Razonar, uni, etc} you can take it serious.

Regards

Fin-Heatexchanger_solved.sm (36,13 KiB) scaricato 1481 volta(e).

Thank you very much!

Wrote

I need to solve the diff the function q.total(t.0) to find its maximum value.

As given you have the range of minimum values.
For min/max of function ... Golden Ratio.

Wrote

Thank you very much!

Sometimes general numeric solvers; solve(), roots(), FindRoot(); struggle with functions involving diff(), int(), sum(), profuct(), if(), cases(), etc.

In your case solve() could answer it. There are some situations which can't be answered by general numeric solvers.

Usually al_nleqsolve(), maple() or Maxima() can solve them.