Exponential Fit Problem...

See WA30 attached.  Why the error?  The variable that represents the vector is in vector form.  If I need to change this to THAXexa := ([1988.0, 1989.0, 1990.0 , ... etc], datatype=float, is there an easy way to convert the THAXexa matrix?

Thanks, Les  WA30.mw

Exponential models?...

In Maple 2015 is there a way to fit data to an exponential model and determine the goodness of fit?

Les

asymptotic expansion of f ...

In some cases, maple is able to return a series expansion when line A is called but fails to do so when line B is called, and in the help page for asympt it defines them to be identical procedures:

A: asympt(f,z)

B:

this has generally occured when ever the function f is of the form:

where g(z) has an asymptotic expansion and when asympt(f,z) is called, maple provides this expansion divided by the exponential function, however line B as prescribed above returns an error.

So, my question is, which line in showstat(asympt) is responsible for catching the error which line B as above encounters?

Trouble taking partial derivatives with e^(y) type...

HI, I'm new to maple and am having trouble taking partial derivitives. I couldn't find anything in the documentation that seemed to resolve the situation, and can't be the first person to stumble through this part of Maple.

Namely, it seems like the exponential function causes an extra "ln()" term to show up in the solution. I've tried with e^(y) and exp^(y) but nothing seems to be working. When i use the same markup up in wolfram and matlab and Ti-CAS i get the "correct" solution.

I attached a screen showing my input and output.

thanks for any insight!

How can I solve this symbolic nonlinear system?...

I meet a interesting nonlinear system in the analysis of an mechanics problem. This system can be shown as following:

wherein, the X and Y is the solutions. A, B, S, and T is the symbolic parameters.

I want to express X and Y with A, B, S, T. Who can give me a help, thanks a lot!

PS:the mw file is given here.

A_symbolic_nonlinear_system.mw

Why do functions with exponential integrals show s...

Hi all,

I am trying to plot in semilog scale a function involving products of exponential integrals and complex exponentials. For small and moderate values of the argument, the plot is well shown. However, for larger values the plot shows strong fluctuations. I was wondering how one can deal with such a problem. Any help is highly appreciated.

Please refer to the attached script for the functio of interest.

Thanks
F

Question.mw

by: Maple

 >
 (1)
 >
 (2)
 >

Problem with plot...

hi all,

Im trying to plot an exponential function which has 2 variables times a constant coefficient. like A*exp(-f(x,a))

When A gets larger, maples fials to plot a smooth curve! how can I solve this problem?

please see the attached file. If rho grows to 0.9, in the first line, you can see when it gets bigger, the cosnstant coefficient of Eq. (7) gets larger rapidly and the plot goes crazy!

sz2012_4m.mw

Nonlinear regression...

Hello everybody,

I have an nx2 matrix of (t,w) , I need to fit a curve of the form of w = A(t-b)c to the data. What I have already tried is to pick a value for b, then regress log w on log (t-b) linearly, which is not very accurate. I'd  greatly appreciate any comments that could help me to find the optimum values for A, b and c through regression methods.

Thanks a lot,

Haley

expansion in a differential equations...

guys ,

in a differential equation i want to expand its variable, but i  have some problem with it for exponential term :jadid.mw

thanks guys

how to find the pairs of solutions [x,y] for x^2+y...

I currently have a function quadsum(n) that determines the [x,y] solutions of the above equation for an integer n. :

local
k:= 0, mylist:= table(),
x:= isqrt(iquo(n,2)), y:= x, x2:= x^2, y2:= y^2;
if 2*x2 <> n then x:= x+1; x2:= x2+2*x-1; y:= x; y2:= x2; end if;
while x2 <= n do
y:= isqrt(n-x2); y2:= y^2;
if x2+y2 = n then k:= k+1; mylist[k]:= [x,y] end if;
x:= x+1; x2:= x2+2*x-1;
end do;
convert(mylist, list)
end proc:

How would I alter this so that I get [x,y] for n= (5^a).(13^b).(17^c)(29^d) for non-negative integers a,b,c,d?

apply convert(,exp) to matrix...

Hi all,

I am stuck with the following problem:

convert(cos(alpha), exp); works fine for me.

Once I have the trigonometric functions in a matrix, it does not work any more:

In the latter line, A keeps the trigonometric functions. Why is this the case? Is there any way to force maple to keep the complex exponentials instead of trigonometric functions?

I am using LinearAlgebra and VectorCalculus.

Best Regards

Wassja

simplification of complex exponentials...

How do I make "simplify" function to recognize complex exponentials. Maple created some exponentiol functions with a square root of negative expression in the denominator of the exponent. It refuses to simplify it. If I manually edit it, by taking negative sign under the root and adding immaginary number, the simplification works. How do I simplify it without manual edit?

The Eq 33 is manually edited line. Simplify function correctly uses cos function.

The Eq 34 is original expression. I tried to tell maple to assume real numbers hoping that it will wotk, but it did not.

bivariate generating function...

Greetings to all.

Just a quick question, probably something obvious, please bear with me Your patience is appreciated.

As part of solving a posted problem at math.SE it became necessary for me to compute the bivariate generating function

`sum(sum(binomial(2*q,n-1)*z^q/q!, q=0..infinity)*w^n,n=1..infinity)`

The correct answer (in fact a simple computation) is

`w exp(z(w+1)^2).`

When asked to compute this sum with the command shown, Maple produces

`hypergeom([], [], z) w`

My question for you is, how does this represent the above answer that I computed manually? When I simplify the hypergeometric, Maple says

`w exp(z)`

which would appear to be the wrong value. Could someone enlighten me regarding this discrepancy?

BTW there seems to be no tag "hypergeometric" and I don't have enough points to create it.

Best regards, Marko Riedel

Issues with the displayed result from performing a...

Hi

Fairly new to Maple and having trouble with the result displayed when using exponential functions.

So I have the following function h(r), in which f1 - f5 are unknown constants that are to be calculated. [I am attempting to set up the equations needed to do so]:

h := r → exp(f1 + f2r + f3r+ f4r3 + f5r+ f6r5)

Firstly, I need to evaluate h(r) at the point A. But, on entering the evaluate command, the general expression for h is re-produced:

A := 0.2

evalf(h(A))

exp(f6r^5+f5r^4+f4r^3+f3r^2+f1+f2r)

Further, I need to take the natural logarithm of h(A), which produces:

evalf(ln(h(A))

ln(exp(f6r^5+f5r^4+f4r^3+f3r^2+f1+f2r))

How do I get Maple to output the actual result of the substitution of r=A and the logarithm?

i.e. how do I get maple to display:

f1 + 0.2f2 + 0.04f3 + 0.008f4 + 0.0016f5 + 0.00032f6

Apologies if this is a very basic question.

Cheers

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