# Items tagged with realreal Tagged Items Feed

### Float(undefined) error when trying to...

May 03 2013 by Maple

2

1

Hi, was wondering if any of you could help me, when I try and find the real part of a function to plot, I get a float(undefined) error, however by just using evalf if gives gives me the real and comlex parts.

zetaroots.mw

The function i want to find realy parts for is f(x).

Thanks,

Matt

### Another proof of stunningly beautiful...

March 13 2013 by

3

3

I propose a different proof of this remarkable identity (see  http://www.mapleprimes.com/posts/144499-Stunningly-Beautiful-Identity-Proved ) in which  directly constructed a polynomial, whose root is the value of LHS, and this is expressed in radicals.

For the proof, we need three simple identities with cubic roots (a, b, c -any real numbers):

### How do you get Maple to calculate with...

August 07 2012 by Maple

1

8

Hi,

I'm using Maple to carry out some calculations in Tropical algebra, which requires taking minima of real numbers and infinity.

I'm currently using symbols rather than real numbers, which is causing a problem, I have (for example) the following lines of Maple code:

> assume(0 < a)
> min(a+infinity, 2*a+infinity)
min(a~ + infinity, 2a~ + infinity)

### What is the proper syntax for the Regula...

July 11 2012 by Maple 15

0

5

I am trying to determine if a particular system of 15 polynomial equations in 9 variables has a real solution using Maple's RegularChains library.  I am using the IsEmpty command which returns true if there are no solutions and false otherwise.  In Maple 16, this can be done using the command:

IsEmpty( sys, R ) ;

where "sys" is a list of equations and "R" is a polynomial ring, both of which I define in the worksheet.  But this syntax only works...

### Using MatrixPower in a sum command

May 28 2012 by Maple 16

2

3

I'm very new to Maple and I'm just curious as to how Maple computes its summations with the MatrixPower command.

if A = a real square matrix

c = some real constant

x = c*A

then Why is it, that when I try to use...

sum(MatrixPower(x,k), k = 0..3);

I get a non-real / ridiculous result, but when I type it out...

MatrixPower(x,0) + MatrixPower(x,1) + MatrixPower(x,2) + MatrixPower(x,3);

x^0 + x^1 + x^2 + x^3;

### Working with "selfreproducing" trees

April 11 2012 by Maple

0

2

Dear members,

I would like to generate a tree (the simplest "stage tree"that I have in mind is in the attached file) ad to work with it. For that I need to  "replicate" [the stage tree which starts in O (with some value R)] after the nodes x2, y2, z2. The nodes x1, y1, z1 are terminal (with values f(R), g(R), h(R) ).

I found soemthing on the posts on mapleprimes, but it is only bor "binarytrees".

How may I proceed?.

I really...

### Re / Im with dirac not working ??

March 11 2012 by Maple 15

I use Maple 15 and I want to take the real and the imaginary part of a simple expression e.g. 5*Dirac(x)+3*I, having already assumed x a real value. However, Maple seems to have problem with the Dirac function. The output looks like this:

> assume(x, 'real');> Re(5*Dirac(x)+3*I);                         5 Re(Dirac(x))> Im(5*Dirac(x)+3*I);                       3 + 5 Im(Dirac(x))

Any thoughts on how to overcome this are welcomed.

### How to solve equation with Real and...

January 19 2012 by Maple 14

Dear All,

I am trying to solve the following equation in Maple but could not find the actual result:

P:=1/2 * Real (E x H*)

How to find the real value of (E x H) with H*= H conjugate.   And also which command to solve for the value P.

Your help will really be appreciated

A.Q

Soton

### why does evalc give csgn?

July 17 2011 by

0

2

Hi,

I am trying to simplify the expression s as given below. (I am not sure why it comes up with all the vector caclulus notation in it but it should display okay when you enter it)

Because of the presence of the exponential imaginary fucntions I thought evalc might be useful but when I use it I get a huge expression with csgn appearing in it. To my knowledge csgn appears when assumptions are not correctly specified - is this so? I can't see any assumption...

### unwilling imaginary part

May 18 2011 by Maple

0

5

Hi,

I'm trying to model a magnetic field with maple.

In order to do that, I compute a (huge) sum and integrals of real and posive numbers.

The problem is that for some points, when I compute the norm of this field I get an imaginary number with a very small imaginary part (egs -2, 27293.1844462+1.42305652280*10^(-84)*I ).

How can I get rid of it?

### Ho to isolate the real part of the equat...

March 08 2011 by Maple 13

0

2

Would you recommend me how to isolate the real and imaginary part and simplify the equation A? Maple cannot evaluate this equation to numeric value...

A := evalf(sqrt((Re(B))^2 + (Im(B))^2));
A := evalf(abs(B));

are not working.

I have attached my equation function.txt

### Cube roots not given the output I expect...

February 22 2011 by Maple

0

2

AHOY! when I compute the cube root of -8 using maple  14.  It gives me the output -8^(1/3)

my input was........

f:=x->

f(-8)

I would like maple to give me the answer of -2 How do I change that? Note I need to define the cube root as a function.

Thanks

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