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Re: Maple can't solve a system of equations but GeoGebra can?

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Try :solve(sys); [allvalues(%)];

The following shows what you actually ask for:
Sys:=(expand(sys));
subs(exp(a) = sqrt(t), Sys); solve(%);

Or even better:
subs(exp(a) = sqrt(t), Sys); eliminate(%, c);


Then just solve exp(a) = sqrt(t) for a.

Likewise evaluate to numerical values.

So there are 3 solutions

PS: You may use http://www.mapleprimes.com/recent/all for questions.
It is alive instead of this usenet group.



On 10.11.2019 21:15, Rainer wrote:
> Hi,
> 
> I'm a student in high school and we're using MAPLE and GeoGebra in
> math classes.
> 
> I've stumbled across something weird: I can't make MAPLE (2016) solve
> the following system of equations, but I can do so with GeoGebra
> (5.0.5). That can't be right.
> 
> Is there a way to make MAPLE put out the numerical solution like
> GeoGebra does?
> 
> Thank you for your help!
> Rainer
> 
> 
> MAPLE:
> =========
>> restart:S:=t->c*exp(-a*t)+18;
> 
>                       S := t -> c*exp(-a*t)+18
> 
>> sys:={S(2)=55,S(8)=36};
> 
>          sys := {c*exp(-8*a)+18 = 36, c*exp(-2*a)+18 = 55}
> 
>> solve(sys);
> 
> {a = -1/2*ln(18/37*RootOf(18*_Z^3-37)^2), c = 37*RootOf(18*_Z^3-37)}
> 
> 
> fsolve doesn't do the job, either:
> 
>> fsolve(sys);
> 
>     fsolve({c*exp(-8*a)+18 = 36, c*exp(-2*a)+18 = 55},{a, c})
> 
> 
> 
> GeoGebra:
> =========
> S(t):=c*exp(-a*t)+18
> 
>      S(t):=(c * e^(((-a) * t))) + 18
> 
> system:={S(2)=55,S(8)=36}
> 
>     system:={(c * e^(((-2) * a))) + 18 = 55, (c * e^(((-8) * a))) + 18
> = 36}
> 
> lsg:=NLöse(system)
> 
>     lsg:={a = 0.1200910257913, c = 47.04478235943}
> 
> SS(t):=Numerisch(Ersetze(S(t),lsg))
> 
>     SS(t):=(47.04478235943 * ?^(((-0.1200910257913) * t))) + 18
> 

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Thread

Maple can't solve a system of equations but GeoGebra can? Rainer <Rainer.Poop@Rcpt.at> - 2019-11-10 21:15 +0100
  Re: Maple can't solve a system of equations but GeoGebra can? "Nasser M. Abbasi" <nma@12000.org> - 2019-11-10 22:42 -0600
    Re: Maple can't solve a system of equations but GeoGebra can? Rainer <Rainer.Poop@Rcpt.at> - 2019-11-12 17:00 +0100
  Re: Maple can't solve a system of equations but GeoGebra can? Axel Vogt <//noreply@axelvogt.de> - 2019-11-11 22:19 +0100
    Re: Maple can't solve a system of equations but GeoGebra can? Rainer <Rainer.Poop@Rcpt.at> - 2019-11-12 17:04 +0100
    Re: Maple can't solve a system of equations but GeoGebra can? Ali Guzel <adrguzel@gmail.com> - 2021-01-17 08:27 -0800
      Re: Maple can't solve a system of equations but GeoGebra can? acer <maple@rogers.com> - 2021-01-17 19:56 -0800

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