MaplePrimes Questions

How to write procedure to find factorial n? Induction to be used.

 

I just quickly checked Nasser Abassi 12000.org to see if he's updated it for Maple 2017.  In some areas he has.  I thought I would check one of the integrals that failed for Maple in his tests.  In the Computer Algegbra independent integration tests Maple failed to solve 11.68% of the 3407 integrals in his test while Mathematica only failed 0.88%.  For Maple that seemed quite high, so it is perhaps his method of solving for Maple and perhaps he's more adept with Mathematica. 

Here is one of the failed integrals and the single line code he used to solve it.

int((5*x^2+3*(x+exp(x))^(1/3)+exp(x)*(2*x^2+3*x))/x/(x+exp(x))^(1/3),x) # of course because it failed it just spits back the integral.

Can maple solve it?

The answer is supposed to be

I am interested to know difference between eval and evalf. Will evaluating a function at a point using these commands gives the same answer or not. I mean will there will be any exception or not. How can I evaluate the value of  a series using eval instead of evalf without the problem of memory running out (No comprimise in accuracy).

Hi all I am attempting to use the randpoly feature to generate a random polynomial of 1st degree with non-zero coeffs between -2 and 2.

I have tried the following:

factor1 := randpoly(x, dense, degree = 1, coeffs = rand(-2 .. 2))

unfortunately as you will find quite often this produces the polynomial "0".  Which it is very clear this is not wanted.

 

Any ideas would be appreciated.

 

Thanks,

Mark

Hi, 

I need to solve system of 6 non linear equations. 

Down here you can see the code I wrote and at the end used to fsolve function, and it is not running. I get an error about the const 'V': Error, (in fsolve) V is in the equation, and is not solved for.

What is the right way to solve this system?

Thank you very much!

 

 

omega1 := 1.562;
omega2 := 2.449;
omega3 := 3.325;
y1 := c1*sin(omega1*t+phi1)+c2*sin(omega2*t+phi2)+c3*sin(omega3*t+phi3);

 

 

y2 := .1019*c1*sin(omega1*t+phi1)+.75*c2*sin(omega2*t+phi2)+.4608*c3*sin(omega3*t+phi3);

 

 

y3 := .407*c1*sin(omega1*t+phi1)+(0*c2)*sin(omega2*t+phi2)+1.844*c3*sin(omega3*t+phi3);
 
eq1 := subs(t = 0, y1) = 0;
 
eq2 := subs(t = 0, y2) = 0;
 
eq3 := subs(t = 0, y3) = 0;
 
eq4 := subs(t = 0, diff(y1, t)) = V;
eq5 := subs(t = 0, diff(y2, t)) = 0;
eq6 := subs(t = 0, diff(y3, t)) = 0;

 

 

eqs := [eq1, eq2, eq3, eq4, eq5, eq6];
 
vars := [c1, c2, c3, phi1, phi2, phi3];
 
fsolve({eq1, eq2, eq3, eq4, eq5, eq6}, {c1, c2, c3, phi1, phi2, phi3});
 

 

Hello all, 

I am trying to compute the Groebner basis for a set of 3 coupled nonlinear equations. The variables I wish to solve for are A0,B0, and B1; however, my equations also have the variables DC, a, nu, q, and t. I wish to solve the 3 equations in terms of these other 5 variables such that I can substitute in any values I desire and obtain a result. When attempting to put the three equations into the PolynomialIdeal command from the PolynomialIdeals package, Maple gives me an error stating that the inputs must be polynomials with respect to all 8 variables. How would I go about declaring the other 5 variables such that they are considered arbitrary constants? 

I was able to get around the errors by assigning values to these 5 variables, though this is not what I am trying to accomplish. I need these 5 values to remain arbitrary.

I am very new to the concept of Groebner Bases and these commands so any help would be appreciated. I have attached my worksheet for reference. I am also happy to supply any additional information that may be needed to assist with this issue.

Thanks!
 

restart

NULL

``

SED2 := proc (A0, B0, B1) options operator, arrow; (32/3)*(nu+7)*A0^2*Pi*DC/(a^2*(1+nu))+3*DC*Pi*((1+nu)^4*(B0^2+(13/42)*B1^2+(4/5)*B0*B1)*a^2+(328/315)*A0^2*(1+nu)^2*((B0+(142/451)*B1)*nu^3+((323/41)*B0+(1490/451)*B1)*nu^2+(11*B0+(3874/451)*B1)*nu-(1847/41)*B0-(8034/451)*B1)*a+(128/105)*A0^4*(nu^4+18*nu^3+132*nu^2+494*nu+939))/(t^2*a^2*(1+nu)^4)-(1/6)*q*a^2*A0-(-(1/4)/a^2-(1/4)*(5+nu)/(a^2*(1+nu)))*A0*q*a^4-(1/2)*(5+nu)*A0*q*a^2/(1+nu) end proc;

proc (A0, B0, B1) options operator, arrow; (32/3)*(nu+7)*A0^2*Pi*DC/(a^2*(1+nu))+3*DC*Pi*((1+nu)^4*(B0^2+(13/42)*B1^2+(4/5)*B0*B1)*a^2+(328/315)*A0^2*(1+nu)^2*((B0+(142/451)*B1)*nu^3+((323/41)*B0+(1490/451)*B1)*nu^2+(11*B0+(3874/451)*B1)*nu-(1847/41)*B0-(8034/451)*B1)*a+(128/105)*A0^4*(nu^4+18*nu^3+132*nu^2+494*nu+939))/(t^2*a^2*(1+nu)^4)-(1/6)*q*a^2*A0-(-(1/4)/a^2-(1/4)*(5+nu)/(a^2*(1+nu)))*A0*q*a^4-(1/2)*(5+nu)*A0*q*a^2/(1+nu) end proc

(1)

NULL

``

eqA0 := proc (A0, B0, B1) options operator, arrow; diff(SED2(A0, B0, B1), A0) end proc:

eqB0 := proc (A0, B0, B1) options operator, arrow; diff(SED2(A0, B0, B1), B0) end proc:

eqB1 := proc (A0, B0, B1) options operator, arrow; diff(SED2(A0, B0, B1), B1) end proc:

NULL

``

type(SED2, polynom);

true

(2)

type(eqA0, polynom);

true

(3)

type(eqB0, polynom);

true

(4)

type(eqB1, polynom);

true

(5)

NULL

``

with(Groebner):

with(PolynomialIdeals):

NULL

NULL

WL := PolynomialIdeal({eqA0(A0, B0, B1), eqB0(A0, B0, B1), eqB1(A0, B0, B1)})

Error, (in PolynomialIdeals:-PolynomialIdeal) generators must be polynomials with respect to, {A0, B0, B1, DC, a, nu, q, t}

 

NULL

type(WL, PolynomialIdeals:-PolynomialIdeal);

false

(6)

``

NULL

GB := Basis(WL, lexdeg([B0, B1], [A0]))

Error, (in Groebner:-Basis) the first argument must be a list or set of polynomials or a PolynomialIdeal

 

NULL

``

GB[1];

GB[1]

(7)

GB[2];

GB[2]

(8)

GB[3];

GB[3]

(9)

``

``

A00 := solve(GB[1], A0):

A00 := simplify(remove(has, [A00], I)):

A0 := A00[1]

Error, invalid subscript selector

 

B10 := solve(GB[2], B1):

B10 := simplify(remove(has, [B10], I)):

B1 := B10[1]

Error, invalid subscript selector

 

B00 := solve(GB[3], B0):

B00 := simplify(remove(has, [B00], I)):

B0 := B00[1]

Error, invalid subscript selector

 

NULL

``


 

Download Groebner_Basis_Work.mw

 

Dear all

I have an operator given below in the image. I want expand this operator upto order 5, when there are three independent variables x, y, t(i=1,2,3). The expansion can also be obtained manually, but that is always prone mistake, is the expansion posible using any routine of Differential Geometry package?

Problem.mw

Hi,

I want to know the partial derivative of

where

in order to 

ρ

If I write 

I obtain this

 

which is incorrect  since I did not have any indexes in sigma. However if I do this next command the result seems correct although no substituion of rhocrf

What I would like to obtain was the solution in order to rho and not to rhocrf and additionally having the result as a summation over p and q and not the extended result. How should I write it in Maple then? 

 

Thank you very much!

I have installed maple in my 64 bit linux and on running calculation a window pop up saying kernel connection not available. I have disabled my firewall still the problem persist. The window freezes on clicking menu. Thankz in advance.

Hi all,

I am trying to display, using mathML, two seperate fractions being multiplied as two seperate expressions with a multiuply in the middle.

as of now I have:

restart:
left:=(x+3)/(x+7):
right:=(x-4)/(x-1):
XMLTools[Print](MathML[Export](left*right)):

The above Maple entry displays as:

I would like:

 

thanks in advance,

Mark

I want(ed) to plot a surface gievn by f(x,y,z),g(x,y,z),h(x,y,z) where k(x,y,z) =0. I suspect that is not possble but I thought I might ask.

 

thanks

Maple does not evaluate

>Re( (2-I*X)^4) ),  assuming((X, realcons)

or

>assume(X, realcons);

> Re( (2-I*X)^4) );

Why do these simple expression return unevealuated?

 

Hi,

I want to apply a rule to simplify an expression. The applyrule command works, when used directly in the worksheet. When I try to use the command within a procedure, Maple throws an error I cannot decipher:

Error, (in PatternMatching:-AlgStruct:-InsertPattern) first operand of `::' must be a name

 

Here is a full demonstration worksheet:

restart:

anexp:=abs(x)^2;

abs(x)^2

(1)

simplify(anexp);

abs(x)^2

(2)

rmabssq := proc(inexp)
description "removes the abs^2 construct in an expression":
local ruleabssqared1,ruleabssqared2,outexp:
    ruleabssqared1:= abs(''a''::algebraic)^2= ''a''^2:
    ruleabssqared2:= abs('expand'(-''a'')::algebraic)^2= ''a'':
    outexp:= applyrule([ruleabssqared1,ruleabssqared2],inexp):
    return outexp:
end proc;
 

proc (inexp) local ruleabssqared1, ruleabssqared2, outexp; description "removes the abs^2 construct in an expression"; ruleabssqared1 := abs(''a''::algebraic)^2 = ''a''^2; ruleabssqared2 := abs((('expand')(-''a''))::algebraic)^2 = ''a''; outexp := applyrule([ruleabssqared1, ruleabssqared2], inexp); return outexp end proc

(3)

## does not work :(
rmabssq(anexp);

Error, (in PatternMatching:-AlgStruct:-InsertPattern) first operand of `::' must be a name

 

## works!
ruleabssqared1:= abs(''a''::algebraic)^2= ''a''^2:
ruleabssqared2:= abs('expand'(-''a'')::algebraic)^2= ''a'':
newexp:= applyrule([ruleabssqared1,ruleabssqared2],anexp);

x^2

(4)

 


 

Download applyrule_4.mw

Thanks for your help

Hello,

i have a vector-valued function mapping from R^n  -> R^m
I  compute its Jacobian Matrix as well as the Hessian Matrix of each output with regard to the inputs, which works so far.
Now I would like to use the CodeGeneration package to generate optimized C Code to compute these matrices numerically. This is, where i encounter a Problem:

I would like to optimize Code for all matrixes at once, because they contain common subexpressions. However CodeGeneration::C tells me it is unable to optimize the given input and generates unoptimized code.


I appended an exemplary file to illustrate the problem: Jacobian_Hessian_codeGeneration_tryout.mw

short version:

C(Jac, optimize = tryhard, resultname = JacobianMatrix);
C(H1, optimize = tryhard, resultname = Hessian1); 
C(H2, optimize = tryhard, resultname = Hessian2); 
C(H3, optimize = tryhard, resultname = Hessian3)

works, but is suboptimal.

C([JacobianMatrix = Jac, Hessian1 = H1, Hessian2 = H2, Hessian3 = H3], optimize)

fails to optimize and

C([Jac, H1, H2, H3], optimize)

fails completely.

(With Jac beeing a m by n matrix and H1-3 beeing n by n matrices)

If anyone can tell me what I'm missing here I'd really appreciate the help.

Hi guys ,

Actually i dont know how to solve the following complicated differential equations by numerical methods ,

numerical.mw

 

Thank you for your attention to this matter

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