Solve error

Solve error - error x - not defined in Solve function - Mensajes

#1 Publicado: 26/3/2014 10:49:45
PKlijn

PKlijn

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I'm trying to solve a equation for x but I'm getting an error (x - not defined) what am I doing wrong?



see the attached screen shot.

Best regards,

Peter

Solve((ρ.M*h.M/x*(r+h.M/2)^2+ρ.B*(r+x/2)^2)*ω.max^2≡σ.ttB_max/{3*f.RS}-E.B*((h.M*α.M+h.R*α.R)/r.o-α.*{ΔT.max-ΔT.min}/2,x)=#@#

Knipsel.JPG
#2 Publicado: 26/3/2014 11:14:51
Вячеслав Мезенцев

Вячеслав Мезенцев

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I think the answer is too big for visualisation.
Russia ☭ forever, Viacheslav N. Mezentsev
#3 Publicado: 26/3/2014 15:13:51
Martin Kraska

Martin Kraska

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Wrote

I'm trying to solve a equation for x but I'm getting an error (x - not defined) what am I doing wrong?


You need to ask for symbolic optimization. The solutions are returned as a list of equations x=..., in your case three of them, and yes, they are really big but they display within seconds.

See the handbook-page "Function index"> "Solve()" to see how to assign selected solutions to variables.
solve.PNG
Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9
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Radovan Omorjan 28/3/2014 2:28:00
#4 Publicado: 26/3/2014 15:25:17
Henrique

Henrique

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Martin, i'm trying do call a maxima function "elliptic_kc()", but it returns an error.

Sem título.jpg
#5 Publicado: 26/3/2014 17:30:24
Martin Kraska

Martin Kraska

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On my computer, Maxima 5.31.1-1 gives the same error message in wxMaxima as reported by you. Thus, this question might be directed to some maxima forum.
Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9
#6 Publicado: 26/3/2014 17:55:41
Davide Carpi

Davide Carpi

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for m = 1 the function may be divergent (x=±π/2):

[MATH eng]elliptic_kc(m):int(1/sqrt(1-m*sin(x)^2),x,0,π/2)[/MATH]

The Maxima manual said:
Citar

For certain values of m, the value of the integral is known in terms of Gamma functions. Use makegamma to evaluate them.



maxima: elliptic_kc
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Martin Kraska 26/3/2014 20:05:00
#7 Publicado: 26/3/2014 20:07:54
Martin Kraska

Martin Kraska

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Thanks, Davide, for having a closer look.
elliptic.PNG
Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9
#8 Publicado: 27/3/2014 9:16:41
Henrique

Henrique

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Thank you all. It was a subtle bug, I just do not let the sine equal to 1 to find the elliptic integral. Anyway, now it runs.
Elastica.sm (18,31 KiB) descargado 1409 vez(es).
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Martin Kraska 27/3/2014 10:52:00
#9 Publicado: 27/3/2014 10:50:40
Martin Kraska

Martin Kraska

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Here is a version using the parametric plot capabilities of Draw2D().
Elastica.sm (19 KiB) descargado 1445 vez(es).
Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9
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Radovan Omorjan 28/3/2014 2:28:00
#10 Publicado: 27/3/2014 16:24:25
PKlijn

PKlijn

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Wrote

Wrote

I'm trying to solve a equation for x but I'm getting an error (x - not defined) what am I doing wrong?


You need to ask for symbolic optimization. The solutions are returned as a list of equations x=..., in your case three of them, and yes, they are really big but they display within seconds.

See the handbook-page "Function index"> "Solve()" to see how to assign selected solutions to variables.



Can you send the Smath file, it is not clear to me how to assign the selected solutions to variables.
#11 Publicado: 27/3/2014 23:10:07
Henrique

Henrique

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Very good Martin. Awesome the power of Draw2D(). It reduced the processing time dramatically.
#12 Publicado: 29/3/2014 4:00:28
Martin Kraska

Martin Kraska

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Wrote

Can you send the Smath file, it is not clear to me how to assign the selected solutions to variables.




_Solve.sm (31,23 KiB) descargado 1422 vez(es).
Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9
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