Hai everyone.

I try to double integrate this generalized extreme distribution.

q[p] := 6.256: h := .8; t[c] := .45: S[di] := 0: k[v] := .32639: mu[v] := -0.1786e-1: sigma[v] := 2.1694: k[t] := .36132: mu[t] := .63543: sigma[t] := 3.1183:

int(exp(-(1+k[v]*(v-mu[v])/sigma[v])^(-1/k[v]))*(1+k[v]*(v-mu[v])/sigma[v])^(-1-1/k[v])*exp(-(1+k[t]*(t-mu[t])/sigma[t])^(-1/k[t]))*(1+k[t]*(t-mu[t])/sigma[t])^(-1-1/k[t])/(sigma[v]*sigma[t]), [v = q[p]/(2*h*t)+q[p]*t[c]/(2*h)+S[di] .. infinity, t = 0 .. infinity]);

however, I got an error, as follow:

Error, (in assuming) when calling '`root/fraction`'. Received: 'numeric exception: overflow'

Any recomendations and tips to solve this integration? or this integration may cannot solve?

Thank you.

I have an expression like this:

Since it is linear I want Maple to rewrite it into this:

(with the benefit that Maple then can solve it at least up to a point). i have tried to conceive a rule to do that but got stuck relatively quickly. Does anybody have a way to do this (in some genrality)?

Thanks,

Mac Dude.

Hi, I want to define functions recursively... 

I don't know how to do it with the for loop in Maple.

I have a[0](t)=0, a[1](t)=t, and then some recursion connecting a[j+1](t) = f( a[j](t), a[j-1](t)) for some explicit function f. 

Then I want to plot the graph of a[N](t) as a function of t. 

Thanks!!

Hi, please a Need a help.
I have an error in my code: Error, (in collect) cannot collect 0
Here, is the code:
Question8X.mw

Many thinks.

Hello,

I am a student and using Maple to type homework assignments because of the math symbols available.  I was using Maple 17 but upgraded to 18, and its not as easy to use as 17.  For right now I am using it in text mode, because that is what I need.  But I can't figure out an easy way to do subscripts and superscripts in text mode.  Also, the "element symbol," where is it?  I feel like a lot of stuff is missing.  For instance, the arrows, the sideways triangle, lots of symbols I used before the upgrade I cant find.  Can someone help please???

After using Simplify the indices are are arranged in the tensor.  I am using the April 14th update from the Physics R&D page.

Download Vacuum_Solutions_(Kerr-Schild)_3.mw

Here is a problem I have with the Nabla operator:

I am working on a demonstration involving Maxwell's equations:

restart:with(Physics[Vectors]);
Setup(mathematicalnotation = true);
# Maxwell's eqn
M4 := `&x`(Nabla, B1_(x, y, z, t)) = mu*epsilon*(diff(E1_(x, y, z, t), t));

eval(subs(B1_(x,y,z,t)=Bxx(x,y,z,t)*_i+Bzz(x,y,z,t)*_k,M4)); # transverse magnetic field, no longitudinal (j) component

# Ok, this one is as expected.

eval(subs(B1_(x,y,z,t)=Bxx(x,y,z,t)*_i+Bzz(x,y,z,t)*_k,M4)) assuming real;

# Hmm... why is this zero?

eval assuming real seems to make them all zero. In this little example, Bxx and Bzz are just arbitrary functions and therefore the result cannot be zero in general. The bother here is that I later use a parametrization of the field (the Bxx and Bzz) which in fact does make curl(B) = 0. I wanted Maple to demonstrate that the parametrization does that, but it appears i can make the result zero for any B-field, which sort-of defeats the purpose. If I don't assume real, with the other parametrization Maple isn't getting anywhere...

So, how can I get correct results while declaring variables to be real when they are... ?

Thanks,

M.D.

Maxwell_test.mw

In Physics[Vectors] the operation ChangeBasis exists to change between different coordinate systems (Carthesian, cylindrical and spherical). The cylindrical system uses the third coordinate (_k) as its axis.

As it happens, in my work the axis of the cylindrial system should be the 2nd one (_j). I do not want to reformulate everything as this would become non-standard and confusing. I am wondering whether it is conceivable to "retrofit" the Physics package to allow for that. At issue are not so much the formulae; I can do the transformation "by hand", but that is a bit clumsy and I am looking for a way to have this integrated better in the Physics package so that all other operations (e.g. Nabla) do the expected.

I have looked for and not found something like an "addBasis" command. Am I missing something obvious here? I should add that some of my work happens on Maple 15 (Mac OS X PPC so no upgrade possible); if something like this was added recently I may have missed it, although I do have access to Maple 17 as well so I could use that version for this particular problem. Is the source of Physics actually open?

TIA,

Mac Dude

Hi! 

When trying to find the fundamental solution of the Heat equation using Maple (software), I get the following Error message which seems to have no documentation available (?) :

Using :

          PDE := -(diff(f(x, t), t))+(diff(f(x, t), x, x))*Di = 0

assume(epsilon > 0);

pdsys := [PDE, f(x, 0) = Dirac(x-epsilon)];

pdsolve(pdsys, build)

"Error, (in casesplit/K) this version of casesplit is not yet handling the function: Dirac"

Anybody has an idea what that is? (Using Maple 17) . How can I solve this problem ? 

http://en.wikipedia.org/wiki/Heat_equation

Thanking you on Advance, 

Erez . 

Hi,

Please I need help in this subject. I would like to compare the numerical solution obtained by finite difference and pdsolve/numeric.

The equation considred is  diffusion Equation using Forward-time centered-space (FTCS) stencil
The code work well with Dirichlet boundary condition, but I want to let  x=-1  Dirichlet boundary condition but on x=1, we put a Neumann condition likeeval( diff(u(t,x),x),x=1)=1. Thank you very much to put the necessary in the attached code the changment.      
Many thinks.

Change_boundary_condition_in_procedure.mw    

assume f and g are unknown

and assume solve(f, x) = solve(g, x)

f -> a

g -> a

b -> f

b ->g

if assume f = (x+1)*(x+2), g = (x+2)*(x+3)

and a = (x+1)*(x+2)*(x+3)

would like to find map from (x+1)*(x+2) to (x+1)*(x+2)*(x+3)

is it the solution subs(x=(x+1)*(x+2),(x+1)*(x+2)*(x+3)) by composition?

subs(x=(x+1)*(x+2),(x+1)*(x+2)*(x+3))

subs(x=1, (x+1)*(x+2));
subs(x=2, (x+1)*(x+2));
subs(x=1, (x+1)*(x+2)*(x+3));
subs(x=2, (x+1)*(x+2)*(x+3));

6 -> 24
12 -> 60

subs(x=1, ((x+1)*(x+2)+1)*((x+1)*(x+2)+2)*((x+1)*(x+2)+3)); # not 24
subs(x=2, ((x+1)*(x+2)+1)*((x+1)*(x+2)+2)*((x+1)*(x+2)+3)); # not 60

it seems composition is wrong

more difficult and general case should be

f(x,t)  -> a(x,t)

g(x,t)  -> a(x,t)

b(x,t) -> f(x,t)

b(x,t) -> g(x,t)

solve(f(x,t), x) = solve(g(x,t), x) = in terms of t

Hi:

What methods to solve system nonlinear ordinary differential equations in maple?I follow a method to solve system nonlinear ode second order that very fast answer me?

Hi,

I have been looking at some new models of Casio Scientific Calculators and came across with "Fx-115es Plus" Model which seem to have a some sort of simple CAS(Computer Algebra System) built into it.

Two new features which i really liked were

(i) Ability to make any part of the expression inert and simplying the rest.

(ii) Fully Integrated Repeated decimal display for fractions.

I want to ask if there is any builtin commands that can achieve these two effects in maple.

I will give some example for each of these

(i) simplifying say 2^3*2^4 in maple gives 32.

but forexample if i want to make 2 in the bases inert then simplifying the result should give 2^7

if i make 3 inert then the result is 16*2^3

if i make 4 inert then the result is 8*2^4

another example say (2^3)^4 in maple gives 4096

but if i make 2 inert then the result should be 2^12

if i make 3 inert then the result is 16^3

if i make 4 inert then the result is 8^4

In this way it is possible to keep any interesting part of large complex expression unevaluated and simplifying the rest across it to maintain focus on the interesting part.

I know i can try to achieve this effect by using unevaluation quotes but they get messy and harder to track in large nested forms.

Another approach might be to replace the inert parts by explicit undeclared symbols with required assumptions and simplifying, but this is not it.

I know in Maple 18 they have introduced some package called InertForm or something, can it achieve this effect and also mark inert parts of the expression as grey like it is possible for some operators.

(ii) the example for the second is quite obvious, say given the fraction 237/14, evalf of this gives 16.92857143 but a result like 16.9Overscript[285714, _] is more closer to differentiation it from a irrational expansion. Sorry i donot know how to pretty print this here.

Another advantage is when i want to give some large repeating decimal expansion and have maple convert it to fractional form. Currently i have no idea how many times to repeat the decimals explicitly to make maple understand that it is a repeating decimal expansion.

I use "dsolve([ode_1])" command to solve an ODE, and the solution contains lots of " I * ln(cos(m)+I*sin(m)) " expression. As "m" is real, I think this expression is equal to "-m", but the maple command "simplify" do nothing for this expression. Any one who can simplify the expression by using maple ? or ever puzzled by similar problem ?

Hi,

Please I need you to add in the output of my code the order of error defined in the procedure.

Thanks for helping me.

Here, the code.

QuestionNumber2.mw