## Why won't assume and assuming work consistently?...

I am trying to determine when one inequality implies another inequality and I am finding that assume and assuming aren't working consistently for me. I've put the code for my test run below. It seems to work the first time through when I assume mylist[1], but when I assume mylist[2] it always returns false. If I explicitly test is(x>-4) it returns true as it should but if I ask it to determine is(mylist[5]) (which is x>-4 once mylist is overwritten) it returns false? Is there a reason for this? I'm eventually going to need to put it all into a loop that works for any list--is there a way that will guarantee that it will work consistently?

## Why don't these structured types work?...

Why don't these structured types work? > type(Pi, symbol); > evalb(Pi::symbol); > type(Pi, constant); > evalb(Pi::constant); > type(x, symbol); > evalb(x::symbol); > type(x, constant); > evalb(x::constant); > type(Pi, symbol and not constant); > evalb(Pi::(symbol and not constant)); > type(x, symbol and not constant); > evalb(x::(symbol and not constant)); I know we can do it using TypeTools[AddType]( variable, t->evalb(t::symbol and not t::constant) ); but why doesn't the simple version work? Phil

## Maplets/Lists...

How do I extract an element from a list in a Maplet? In Maple, if I wanted the 1st entry in list A, I'd just use A[1]. In a Maplet, the output of a DropDownBox is a list containing a string, but 'DDB'[1] seems to make no sense to the Maplet.

## Relative URL hyperlink within a worksheet...

I want to distribute a collection of Maple-related materials to students or other users. One of the "documents" is a Maple worksheet that contains a hyperlink to other material in the distribution. So, I want to have a URL hyperlink reference to, say, "./web/mystuff.html". It appears to me that Maple's hyperlinks are designed for use only with static, and external, websites. The hyperlink properties popup dialog does not allow me to browse to a local file; I can only browse to a worksheet or maplet. I can get around this limitation by manually editing the worksheet file. I can give an explicit path to the file but I have been unable to find a way to use a relative path to the file.

## Maplet output...

How can I get a Maplet to output a simple real number? What I'm trying to write simply asks for a real number, which will then be used in a worksheet after the Maplet is called. A better question might be, How can I extract a number from a string? Since Maplets appear to output ["123.456"] -- How can I assign the 123.456 to a variable? Thanks, Shannon

## Calculating prime numbers...

Hello, A Maple user sent me a technical support e-mail today with questions about calculating prime numbers, and I thought that it would be worthwhile to post the questions in this forum for our community to answer. The questions are: 1. What is the "best and final" algorithm to find a prime number in Maple? 2. How can you use Maple to calculate the last Mersenne prime number? Bryon Thur Manager, Business Information Systems Maplesoft

## Solutions to sin(x)=sin(1/x)...

When I graph the functions sin(x) and sin(1/x) in maple I can see that these functions will intercept each other an infinite number of times. However, when I write the equation sin(x)=sin(1/x) and click on it and choose solve maple only ruturns the obvious solutions 1 and -1. I can see that sin(1/x) ->0 as x increases (x>2/Pi) and that sin(x) will repeatedly assume all values between 0 and 1 as x increases. In general, how can you find the values where the two functions intercept on some interval where x>1, say [2,10], and also on some interval where x is between 0 and 1? Can I do this with Maple both algebraically and numerically?

## Exporting Maple plots to MS-Word...

You can use export to metafile. The problem is that the created file is not a vector based graphic. So when you print it or when you enlarge it, the pixels appear and deteorate the quality. MATLAB has two options in copying a plot into clipboard: copy as bitmap and copy as metafile. But in Maple the Metafile has not any difference with Bitmap! I do this by exporting my figure to .eps (color or B&W), then importing it from Word. A more complicated task!

## Series test...

is there anyway to use maple for convergince/ divergince test, and also Taylor series in sigma notation?

## Is g the same as f?...

Suppose you have a complicated expression g for what you expect is a simple function f. Suppose also that you cannot find how to simply, combine, expand g in order to get f. What can you do? What I typically do is graph f and g, or graph f minus g. I thought I overheard someone at the Maple 05 Conference say there is a command that checks to see if f and g agree on some mesh. If they do, the command makes some response. Is there such a command? I know I should have interrupted the conversation and asked details, but I didn’t. Maybe someone can help now.

## spin coefficients using npspin...

I need to calculate spin coefficients using a tetrad of null vectors, {l, n, m and m*} that I constructed for a certain metric. The brute tensor calculations are very lengthy, especially for this metric. On the other hand I have tried to use Maple (9.5) npspin; and the example given on the use of npspin. It's not clear from the example whether the entries (1,1),...(2,3)...etc are: 1) from setting the rows of the covariant vectors l, n, m and m* adjuscent to each other(?) to form some 4 X 4 matrix; or 2) from the metric g (elements) through dyadic combinations (1/2)ln+(1/2)nl-(1/2)mm*-(1/2)m*m that form it.