## Finding an unknown function from data...

I am trying to model a disease. The equation is as follows:

S*X - f(X,S,Sp) = 100

I have data for S, I have data for X and I have data for f(X,S,Sp) however I want to find an equation for f(X,S,Sp) that has the best fit with the data because I need to use it later on in my calculation. If anyone is intrested S is the sensitivity of the blood test, Sp is the specificity of the blood test. This means that X*(1-Sp) is the number of false positives.

I currently dont have access to Maple hence I am doing all my modeling in excel 2016. So I am severly limited because excel is useless at algebra.

Maple.xlsx

## why this equation does not any answer?...

hi

why this equation does not any answer?

thanks

 >
 >
 > eq:={-J*g[1]*(diff(w(x), x, x, x, x, x, x))+J*c[1]*(diff(w(x), x, x, x, x))+A*g[113113]*(diff(w(x), x, x, x, x))+(beta[11]*A*0)*`ΔT`*(diff(w(x), x, x))+2*b*f[1133]*(Pi/L)^2*(d[33]*lambda[3]*`ΔT`*L/mu[33]-2*f[1133]*a*Pi/L-P[3]*`ΔT`*L)*sin(Pi*x/L)*sinh(h*Pi/(2*L))/(2*cosh(h*Pi/(2*L))*(-a33+d[33]^2/mu[33])) = 0, w(0) = 0, w(L) = 0, (D(w))(0) = 0, (D(w))(L) = 0, ((D@@3)(w))(0) = 0, ((D@@3)(w))(L) = 0}
 (1)
 >
 >

## Solve... well it depends...

Here is one that the students generated which caused confusion.

a := 0.76;
eq1 := 2*cot(a*sqrt(2*E)) = (2*E-5.4)/(sqrt(E*(5.4-E));
solve(eq1, E)

And the results are: 0., 4.411954070, 2.423743792

The problem is with the second answer because it does not exist. If we plot the LHS and the RHS of eq1 vs E where E=0..5.4

And it gets more interesting, if we calculate:

solve(evalf(eq1), E)

The answers are: 0., 2.423743793, 14.33807304+27.39159712*I

where the 3rd answer is again incorrect.

Finally, if a = 0.8 or larger, the incorrect answers disappear.

Note - fsolve does handle this problem correctly. And despite my attempts to remind them to use fsolve, they see the solve command as the universal truth. Apparently this will be another teaching moment for next year.

So any thoughts about why this happens and why there is a difference in the outcomes between 0.76 and 0.8 for the value of a?

## Error, (in dsolve/numeric/BVPSolve) singularity en...

hi.

how i can dsolve this differential equations?

thanks

## ugh maple 2016 not windows XP supported...

I did not realize Maple 2016, since Maple 2015 actually, had stopped Windows XP support.

## loss of animation when moving worksheet from windo...

When transfering a particular worksheet from my home Windows 7 computer to an office Linux computer I lose some of the end of the worksheet, namely I lose a rather memory intensive animation at the end. And the office compute crashes when I attempt to run the animation. This seems strange since apparently the office computer (see below) is more powerful than my home computer.  When this happens there are apparently few if any other users of the office computer. I  would be grateful for suggestions for remedies for this problem or any ideas of what the problem could be.

Home computer: Windows 7 Intel(R) Core(TM) i7-2600 CPU@3.40GHz, 12 GB RAM 64-bit OS

Office computer: CentOS, Kernel Linux 2.6.32-573.12.1.l6.x86.64, Gnome 2.28.2, Memory 94.4GiB, 6 processors each an Intel(R) Xeon(R) CPU E5-2643 v2@3.5BHz, Available Disk Space 1061.0 BiB

## Maple doesn' t work in pc with Windows 10...

Hello,

I loaded Maple to my friend's PC. But we can not execute any command in worksheet. When we write some lines and hit enter, it does not respond in anyway. (excluding simple calculations such as: 2+3 etc.) What is the problem and how can we solve it?

PC: Windows 10

Maple 2016.1

## Are NetCdf files supported by Maple ?...

Hello all,

A question concerning NetCdf files was asked in 2012 and is still unanswered today.
Browsing the questions only returns this item, suggesting the NetCdf topic is not a concern in the Maple community.
Nevertheless, does it exist some capabilities in reading and writting NetCDF files ?
If not, are there some planned development on the subject ?

Let's hope now for not having to wait four years for an answer, all responses will be greatly appreciated, even negative.

years

PS : NetCdf capabilities already exist in Sage or Mathematica

## Explore function problem....

Can i make Explore with number of parameters differs from parameter in explore?
For excemple i whant to make sum with 'l' values wich will declorate in explore, and 'l' - count of them will declorate in same explore, but it dont work, so is it posible?

 (1)

 (2)

 (3)

## metrics, scalar product...

Dear Friends, I work with physics paсkage. I have a quation. I don't understend how one works with metrics. For example, let:

Nice!
Very good!

1) It doesn't work. Why? (I want exactly gamma_[A,B], rather than g_[A,B], because as i guess gamma_[A,B] has a signature [1,1,1] but g_[A,B] has a signature [-1,-1,-1])

2) And how may I see what is matrices g_[A, B], gamma_[A, B] explicitly? That is I know how to see what is g_[mu, nu], for this one needs write "g_[];".  But how may I see g_[A, B] and gamma_[A, B] in explicitly forms?

3) Why command Trace(g_[mu, nu]))  does not work?"

HI

thanls...

## Cant open saved Maple document...

Hey, this is not the I've had this encounter. I want to open this saved document but when I open it and Maple starts up it just hits me with "A problem was encountered while opening the workbook. Database is not opened". How can I get to open it properly and see my math notes?

How can this be prevented?

When I try to upload the file in this message it says "Cant open a null file"

Any help?

Jacob

I am writing a package to define a few Records and collect some quantities and formulae to do some arithmetic with.

At some point I started running into a severe problem: Each time I want to use one of the exports form the module, the Maple kernel dies with a "Stack limit exceeded" message. The issue is: This seems to happen only on Maple 2016. I had some issues in Maple 2015 but that got sorted by rewriting some stuff. I never had any issue like that with Maple 15. I went as far as commenting out most of my .mapleinit code to make sure that did not cause issues. The code works as intended in Maple 15 and in Maple 2015.

I am posting this here and am asking others to see if they can reproduce this. Needless to say I will SCR this. But I actually need to get this to work.

The error can be triggered by simply entering

Booster;

after loading the package. Needless to say, it should just echo the name "Booster", to get more one would need to enter eval(Booster) (due to the last-name evaluation rules).

Thanks,

M.D.

BooMBA.mw

## Optimization with ramdom variable using NLP...

Dear all!.

I have an expression with ramdom variables. Can i use NLP to optimize it?. In this case, does Maple take the histogram of theses ramdom variables?. Thank!!!

## Expression vs Layout Palette...

What is the difference between the Expression Palette and the Layout Palette? First I thought that the Layout Palette is supporting the entering of names with e.g. sub- and superscripts, but I learned (the hard way) that the templates of the Layout Palette are "mathematically active".

What is the meaning of the colours green and violett in both palettes?

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