## How to change page color...

hi, is there a way to change color of the page in Maple 18? in fact I am preparing my lectures using slideshow option and want to change the color instead of the default white.

## Maple nested loop error: unterminated loop...

Hi,

I'm, trying to write a nested loop in maple, but I keep getting the Unterminated Loop error. I'm sure the solution is quite simple, but I haven't been able to find it. Any suggestions would be much appreciated. The loop looks like this:

i:=0:
di:=25:
n:=1:

while (n<=nLimit) do
sol1:=fsolve(eq1, y=i..i+di)
if type(sol1, numeric) = true then
lambda(n) :=sol1
i:=i+di
n:=n+1
else  i:=i+di
end if:
end do:

## Calculate area using integration...

Hello,

please explain how to write a code to calculate and output the actual area using integration for y=X^3 over range (0,2) using left-hand rule and 200 subdivisions?

Thank you

## finding a solution of system of equation...

please is there any one can help me to find a solution of a sytem of 3 non linear equations each with 3 variable and with more than 30 unknown coefficients

this is the system

solve({EEE_x(x, y, z) = 0, EEE_y(x, y, z) = 0, EEE_z(x, y, z) = 0}, {x, y, z})

where x,y,r are the unknowns

and the three equations are simply the partial derivative with respect to x,y and z repectively

EEE_x(x,y,z):=(&DifferentialD;)/(&DifferentialD; x) EE(x,y,z)

EEE_y(x,y,z):=(&DifferentialD;)/(&DifferentialD; y) EE(x,y,z)

EEE_z(x,y,z):=(&DifferentialD;)/(&DifferentialD;z)EE(x,y,z)

the main equation is EE where (it has 3 variables and more than 30 qunknowns coefficients

(x, y, z) ->

1
----------------------------------------------------------------
2
/ 2 2 2\
hh \ii + jj x + ll z + mm y + 100. y + nn y z + oo x + pp z /

/ 2 2 2 2 3 2
\p z y + q z y + l z x + g z x + o z y + n z x + m y x

2 2 2 3 2 2 2
+ j y x + k y x + i z y + d z y + f z x + h z y

2 2 4 3 2 3
+ e y x + u z y x + v z y x + a + b x + c x + r x + s z

2 2 4 3 4 \
+ t z + bb z + cc y + dd y + ee y + ff y + gg z + aa x/

## Lots of memory errors and leaks in openmaple libra...

This is a question I have also submitted to the technical support, I am worried that it is a bit too technical for them, however:)

I am debugging a C program which links against the OpenMaple API library (under Linux and with Maple 17 and 18). I am using valgrind memcheck, because I am experiencing strange behavior which could be due to writes beyond allocated blocks of memory.

The first thing which jumps to my eye, are many errors of the types

``Use of uninitialised value of size (4/8/16)Invalid read of size (4/8/16)Conditional jump or move depends on uninitialised value(s) ``

The same errors are also printed when I use the examples that ship with Maple. For instance, I compile "simple.c" with

gcc  -Wl,--no-as-needed -lmaple -lmaplec -lrt -L /usr/lib -L \$MAPLEDIR/bin.X86_64_LINUX -I \$MAPLEDIR/extern/include -o simple simple.c

and run valgrind as

valgrind --tool=memcheck --error-limit=no --log-file=memcheck.log ./simple

Some, but not all, of the errors occur in `__intel_sse2_strcpy` or `__intel_sse2_strlen`. Furthermore, according to valgrind there are definite memory leaks. which appear in the library.

Practically this makes it hard for me to identify my potential own errors. I am a bit surprised to see so many warnings because I tend to fix my own programs until memcheck does not print these anymore (before I give it away at least). The question is: Can I consider these errors as safe to ignore? How would I distinguish real errors which may appear in my application?

## Can I use different numerical methods to solve a s...

I'm trying to solve a system of four pdes and I know that the Newton method won't converge.

Are there other numerical methods that I can use?

Any help would be greatly appreciated!

Thanks,

Eve

## algsubs in equation with multiple derivatives...

I am trying to simplify equation 18 using equations 8 and 9. It should look a little like equation 21, but instead I get the results in equations 19 and 20.  I tried using different substituions, but algsubs gets the closest answer. A few terms are going to zero after the substitution.

When I substitute Z(X) then Zbar(X) terms vanish, and visa versa.

 (1.1)

 (1.2)

 (1.3)

 (1.4)

 (1.5)

 (1.6)

I will try to verify the tetrad from (Kerr and Schild (1965)). However, the tetrad given in the paper seems to have the third tetrad with the wrong sign. I changed the sign and get the correct verification,

 (2.1)

 (2.2)

 (2.3)

 (2.4)

 (2.5)

 (2.6)

 (2.7)

 (2.8)

For equation 2.8 we get the following:

 (1)

Now we replicate eqn 2.16. These are the conditions for e[4,mu] to be geodesic and shear-free. The outputs are eqn 3.5.

 (2)

 (3)

 (4)

 (5)

 (6)

 (7)

Now we can define the rotation coefficients associated with rotation and expansion z = theta - i omega

 (8)

 (9)

 (10)

 (11)

We now show that the tetrad vectors are propogated parallel along each curve of the congruence of null geodesics which have e[4,~mu] as tangents.

We now use the tetrad form of the Ricci tensor. In order to use this in Maple we need to create a Ricci Tensor Tetrad function.

 (12)

 (13)

 (14)

 (15)

 (16)

 (17)

The geodesic and shear free condition given by Lemma 1 in (Goldberg and Sachs (1962)). Kerr uses the fourth tetrad instead of the third so we need to modify the Ricci tensor conditions. The equations (2) - (5) enforce the first Lemma.

Notice that none of the previous Ricci conditions can be used to solve for H.  We can use the remaining field equations to find the partial differential equations necessary to derive the metric.

 (18)

 (19)

 (20)

 (21)

## Difficulty with using Explore and plot with parame...

Hi,

I'm trying to create interactive plots by using Explore to help demonstrate the effects parameters have on functions. I created one successfully to illustrate shifts and stretches of a polynomial:

transform(A,B,X,H,P,K):=Explore(plot(a*(b*x+h)^(p)+k,x=X),parameters=[a=A, b= B,h=H,p=P,k=K],placement=right)

However when I try to do the same with a solved ODE it returns an error message:

Explore(plot(1/(-p*x+x+1)^(1/(p-1)), x = -5 .. 5), parameters = [p = -20 .. 20], placement = right);

Executing this gives the error message:

Warning, expecting only range variable x in expression 1/((-p*x+x+1)^(1/(p-1))) to be plotted but found name p
INTERFACE_PLOT(AXESLABELS(x, ""),

VIEW(-5. .. 5., DEFAULT, _ATTRIBUTE("source" = "mathdefault"))),

parameters = [p = -20 .. 20], placement = right

I'm not sure why it is having difficulty dealing with "p" when it had no difficulty with the first. Any help would be appreciated!

## Using Radio Button to define and asingne value to ...

Hello

I wantt to assigne value to a variable that doesn't exist before the radio button. How can i do that?

## How do I resolve "extra unknowns"?...

I am attempting to plot an initial value problem in Maple 18.  I have my equation defined, as well as a general solution and two particular solutions at y(0)=3/4 and y(0)=1/2.  To graph, I entered the command

DEplot(de,y(x),x=-3..3,{[0,1/2],[0,3/4]},dirgrid=[12,12],color=black,linecolor=blue,thickness=2);

but instead of returning a graph, the software gave me the error message

Error, (in DEtools/DEplot/CheckDE) extra unknowns found: sinx

The Maple support site lists this as an unknown error, and as a new user, I'm not sure what to do.  What does this mean?

## List of all labels...

How I can get a list of all label refernces of a worksheet. In fact I want to write a small code which would produce the LaTex output (written to a text file) for my indicated labels. thanx

I am new to Maple. I am working though the manual and in chapter two I tried to get the derivative of ln(x^2+1). I am getting something completely different that the actual derivative. I tried a simple derivatie (the derivative of 2x and get 0). I do not know what I am doing wrong. Any help will be appreciated.

## latex output from ShowSolution ...

I want to put the solution obtained from ShowSolution() command of Student[Calculus1] into my LaTeX file. How I can achieve that?

I succeeded in getting latex of ExpandSteps because it was a module, but ShowSolution() is not a module.

## Loop for a Function...

Hello friends,

I try to write a loop in Maple.

The equation is f (x) = x + 3

x is a variable and should be from 50 to 70 with dx = 5 can be used in the function, so that f (x) is to be determined.

How can I write such a loop?

## Error in calculus sheet...

Hello Maple

I am preparing for an examination in Calculus, but my worksheet in Maple 18 doesn't cooperate.

A lot of my studypartners use Maple 16 and they have no problems.

I meet the following error:

- Error, (in solve) invalid input: hastype expects 2 arguments, but received 1

I'm totally sure, that I'm typing correctly, because I write just the same as my studypartners.
So is it an error, which only is seen in Maple 18 and can I do anything to solve the problem?

Kind regards
Anders Kristensen

PS: I can't figure out how to add a picture

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