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)=#@#

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I think the answer is too big for visualisation.

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.

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

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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.

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:

Quote

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

Thanks, Davide, for having a closer look.

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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.

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Elastica.sm (18.31 KiB) downloaded 1116 time(s).

Here is a version using the parametric plot capabilities of Draw2D().

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Elastica.sm (19 KiB) downloaded 1149 time(s).

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.

Very good Martin. Awesome the power of Draw2D(). It reduced the processing time dramatically.

Wrote

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

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_Solve.sm (31.23 KiB) downloaded 1142 time(s).