## 322 Reputation

19 years, 93 days

## Fit Equation to Data...

Maple 2023

I am attempting to obtain an equation for battery discharge.

I have data from a battery that will supply 25 amps for 210 minutes. I want to fit this to an equation and then try to adjust the curve to match a battery that will supply 25 amps for 160 minutes.

Here is what I have:

restart; with(Statistics):

## Amps
A := Vector([444, 218, 74,312/10,209/10,119/10,625/100]):
## Time until battery discharges to 10.5 volts
T := Vector([5,15,60,3*60,5*60,10*60,20*60]):
f := x -> a*exp(1-x/b); f(x)
eqset := {seq(T[idx] - f(A[idx]), idx=1..7)}
sol := NonlinearFit(a*exp(1-x/b),A, T, x)
evalf(subs(x=A[6],sol))
P1 := plot(A,T): P2 := plot(sol,x=0..450): plots[display]({P1,P2})

I want the 'knee' of the fitted curve to more closely match the measured data.

How do I do this?

## Why will MaplePrimes not allow me to rep...

MaplePrimes

Joe Riel replied.

A couple days later, I attempted to reply to Joe's question. The blue 'Submit' bar continued to flash, never stopping.

I asked this question a few days ago, but, it was deleted as 'Spam'.

This is not spam.

Tom Dean

## Is maplev-mode still supported?...

Maple 2023

Ubuntu 22.04.

I have Maple-202[1-3] and an old installation of maplev-mode. maplev-mode fails to work.

In the emacs messages buffer, I see (typed from memory):

maple not running

I removed all of maplev from my system.
make install fails:

> pwd
/tmp/maplev-master
> make install
Makefile:27: MapleLisp.mk: No such file or directory
make: *** No rule to make target 'MapleLisp.mk'.  Stop.

I tried installing from the cloud, but, failed. The error message (even run as root)

Error, (in PackageTools:-Install) permission denied

Will maplev-mode work?

Tom Dean

## Why do I get different outputs?...

Maple 2023

> ode_sys:=2*diff(x(t),t\$2) + 6*x(t) - 2*y(t) = 0, diff(y(t),t\$2) + 2*y(t) - 2*x(t) = 0:
> lsol:=inttrans:-laplace({ode_sys},t,s)

The displayed output has an unresolved  "=  inttrans/laplace`(0, t, s)" on the end.

> lsol

Does not. Why?

## GF input() accepts out-of-range input...

Maple 2023

I think the GF function, input, accepts out-of-range inputs.

From ?GF: The G:-input and G:-output commands convert from an integer in the range
"0 .. p^k - 1" to the corresponding polynomial and back

GF_strange.mw

The first GF was from a typo. I think it should have produced an error message, according to help.
If I understand correctly, GF(7,1) should only have 7 members.
The second GF is to allow the input 28856.

Tom Dean

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