How to get a max in a solve changing one parameter

Posted on 2008-11-19 22:58 By racing01 (

24)

Categories:

How do I ...? with Maple

Hello

I have this problem:

I have two non linear equations with twos solutions (Ea and F in the picture)

I need the alpha that gives me the max Ea

How can I enter this in maple.

Thanks a lot!

I attach an image of the equations to be more specifyc

It would help a lot

Comment on 2008-11-20 12:26 from jakubi ( Maple Rating 4

943)

if you post your commands in text form and/or upload your worksheet.

Since I'm kind of new to

Comment on 2008-11-20 13:10 from racing01 (

24)

Since I'm kind of new to this forum and maple, I apologize. I'll attach the file

BTW I've learned a lot in the last in the last to two months thanks to you and the books.

In the problem could advance a little bit or at least approach to an answer

In the file wou wiil see a

for i to 17 do

' align='absmiddle'>

solucion[i] := solve({item3[i], item4[i]}, [Ea, F]);

' align='absmiddle'>

alpha[i] end do

' align='absmiddle'>

And What I want for this solution is to make a table with 3 columns alpha, Ea, and F ready to export to an excel and make a graphic to approximate the higher Ea for a determined alpha

But I've never done something similar and I'm lost.

I know the solution is not exact as I'm always working for arphas going from 0 to 90º by 5º, but I don't need to be exact (besides I don't know how to do to find the exact alpha)

Thanks a lot for your help, If you figure another way to solve it, welcome!

View 9175_problem.mw on MapleNet or Download 9175_problem.mw
View file details

diverging

Comment on 2008-11-22 12:49 from jakubi ( Maple Rating 4

943)

In a plot for Ea(alpha) (with the code below) I get that it diverges for alpha aprox 0.25, apparently a pole there (observe the change of sign in your results).

s:=solve({vF*F+vE*Ea+vC,hF*F+hE*Ea+hC},{Ea,F});
subs(s,vF=coeff(lhs(Sumfzasvert),F,1),vE=coeff(lhs(Sumfzasvert),Ea,1),vC=coeff(coeff(lhs(Sumfzasvert),Ea,0),F,0),
hF=coeff(lhs(Sumfzashor),F,1),hE=coeff(lhs(Sumfzashor),Ea,1),hC=coeff(coeff(lhs(Sumfzashor),Ea,0),F,0),Ea):
combine(%,units);
Ealpha:=%/(1000*Unit(kg/m));
plot(Ealpha,alpha=0..Pi/2,-500..500);