## How I can find the constant...

I'm new using maple and I trying to solve this equation:

u*(diff(u*(diff(R(u), u)), u))-(-m^2+u^2+fu)*R(u) = 0

Maple give this solution:

R(u) = _C1*BesselI(sqrt(-m^2+fu), u)+_C2*BesselK(sqrt(-m^2+fu), u)

But I don't know how I can find de constant C1 and C2.

## How to solve for constants Deriving Simple Harmoni...

I am practicing with some diff equations. I am having problem solving for one of the constants. I am having a pproblem assigning a value to derivatives or 2nd derivatives. What is a good general technique is this type of situation?

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by: Maple

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## Forget very small numbers...

Hey,

at some point in my maple calculations I have to read some symbolic constants because otherwise the expressions become to big. All my constants are in a range 1e-3 to 1e6 or something. No matter how exact I calculate my result always has some Numbers in the range of <1e-20 (how small they actually are varies with Digits) together with numbers 1e-3..1e6. I presume those 1e-20 are just zeros. Can I somehow tell maple to forget/drop very small numbers and assume them all to be zero?

Thanks!

Honigmelone

## Problem with integration....

I am performing the int operation on an experssion but it does not consider constants to be constants. For example, maple is considering this constant namely, f'(-1) or eval(diff(f(x), x), x=-1) as a function and henceforth does not give the desired output. Please tell me how to make eval(diff(f(x), x), x=-1) as a constant function or to say, how to convert any given function in to a constant function.

Thank you for your time and help!

## How can i improve my nummerical solution?...

Hello guys ...

I used a numerically method to solve couple differential equation that it has some boundary conditions. My problem is that some range of answers has 50% error . Do you know things for improving our answers in maple ?

my problem is :

a*Φ''''(x)+b*Φ''(x)+c*Φ(x)+d*Ψ''(x)+e*Ψ(x):=0

d*Φ''(x)+e*Φ(x)+j*Ψ''(x)+h*Ψ(x):=0

suggestion method by preben Alsholm:

a,b,c,d,e,j,h are constants.suppose some numbers for these constants . I used this code:

VR22:=0.1178*diff(phi(x),x,x,x,x)-0.2167*diff(phi(x),x,x)+0.0156*diff(psi(x),x,x)+0.2852*phi(x)+0.0804*psi(x);
VS22:=0.3668*diff(psi(x),x,x)-0.0156*diff(phi(x),x,x)-0.8043*psi(x)-0.80400*phi(x);
bok:=evalf(dsolve({VR22=0,VS22=0}));

PHI,PSI:=op(subs(bok,[phi(x),psi(x)]));
Eqs:={eval(PHI,x=1.366)=1,eval(diff(PHI,x),x=1.366)=0,eval(PHI,x=-1.366)=1,eval(diff(PHI,x),x=-1.366)=0,
eval(PSI,x=1.366)=1,eval(PSI,x=1.366)=1};
C:=fsolve(Eqs,indets(%,name));
eval(bok,C);
SOL:=fnormal(evalc(%));

I used digits for my code at the first of writting.

## whittaker functions...

How do I find the constants in a solution containing whittaker functions?

the boundary conditions are:

c(x,0)=1

c(0,y)=1

[c'(1,y),x]=0

## Getting a value of a constant...

Hello everybody,

While doing a document about quantum mechanics, I stumble on this strange behaviour.

>with(ScientificConstants);
>GetConstant();
>GetValue()

Error message:

Error, (in ScientificConstants:-GetValue) `a[0]` is not a scientific constant object

But in the Assistant Scientific Constant, the value is there: 5.291772e-11m

Why is it not directly available like I did the first time?

```--------------------------------------
Mario Lemelin```
```Maple 18 Ubuntu 13.10 - 64 bitsMaple 18 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987```

## MRB constant N part 4

Maple

Let d be the Feigenbaum delta constant 4.66920160910299067185320382046620161..., a be the Feigenbaum alpha constant 2.50290787509589282228390287321821578... and m be the MRB constant 0.18785964246206712024851793405427323....

d*m - 2 (600 a - 2537)/(5 a - 2373) = 9.232940534412995...*10^-19

or you could write

1/10*(d*m + 564446/(2373 - 5 a)) - 24 = 9.232940534412995...*10^-20

## 2,000,000 digits!

On May 17, 2013 I finished a 2,000,000 or more digit computation of the MRB constant, using only around 10GB of RAM. It took 37 days 5 hours 6 minutes 47.1870579 seconds. You can write marvin@marvinrayburns.com for the digits.
The program I used was based on Richard E. Crandall's work:
Richard E. Crandall,Unified algorithms for polylogarithm, L-series, and zeta variants(53 pages)

## Plotting with a constant...

Hello, I have a problem with plotting graphs with a constant.. I have one system of equations and one another equation:

dx/dt=x(t)

dy/dt=ky(t)

and

|y|=C|x|^k

I need to compare theit curves.

k and C are constants. I thought it is alright if I would remove constants, BUT there is one in the power, so I have no idea what to do..

I just tried to plot the system, but it doesn't work either:

## How do i print to PDF the parameters of a model in...

I have a model with 3 parameter blocks containing a lot of constants. I would like to know how can i print those lists to papper, .pdf, word or something like that.

Thanks

## dsolve: additive constants of integration lost...

Hello,

I'm solving a system of 3 second order ODE's for 3 unknown functions, using dsolve. But in the output, I receive various sets of solutions which contain only 3 constants of integration. A friend solved the same system but in Mathematica, and received more constants of integration.

I guess this has to do with the issue that Maple omits additive constants of integration almost everywhere.

Is there some solution? i.e. some way of using...

## Computing the MRB constant in Maple and on the...

Maple

The MRB constant can be computed in Maple by evalf(sum((-1)^n*(n^(1/n)-1),n=1..infinity)).

On my laptop restart; st := time(); evalf(sum((-1)^n*(n^(1/n)-1), n = 1 .. infinity), 500); time()-st gives a timming of 37.908 seconds.

Using the procedure posted at the bottom of this message st := time(); A037077(500); time()-st gives a much faster timing of 1.903 seconds.

My fastest timing for 500 digits of MRB comes from my...

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