## 6472 Reputation

15 years, 339 days
University of British Columbia
Associate Professor Emeritus

## A maple exam in a half and hour, help?...

Be sure to tell us the name of your instructor, so we can tell him/her how much we enjoyed helping you.

## A maple exam in a half and hour, help?...

Be sure to tell us the name of your instructor, so we can tell him/her how much we enjoyed helping you.

## The same problem...

It might help if you uploaded your file. At least we could take a look at it.

## x + y + z = n...

I'm assuming n is a given positive integer. The simplest way is > {seq(seq([i,j,n-i-j],j=0..n-i),i=0..n)}; Somewhat trickier, but not as efficient, would be > with(combinat): convert(map(op @ permute @ (t -> t - [1,1,1]), select(t -> (nops(t)=3), partition(n+3))),set);

## A second Ditto operator?...

It first makes an appearance in Maple 10, I think. I haven't encountered it in any documentation. I suspect it's a side-effect of something else.

## Martingale...

The Oxford English Dictionary says: French martingale is attested earliest in the phrase chausses a la martingale hose that fasten at the back (1491); cf. Occitan braias à la martegala hose that fasten at the back, and Italian martingala (a1556; also 1598 in sense 1 [the horse-harness]), Spanish martingala (1529) in the same sense. The application may arise from a belief that the inhabitants of Martigues, a remote town, were eccentric and naive; hence also the application to an apparently foolish system of gambling. Sense 2 [the ship-rigging], however, is prob. attributable to the former importance of Martigues as a port and ship-building centre. Sense 1 is variously explained: some take as a development from the application to hose (although N.E.D. (1905) holds that the opposite is the case); Französisches Etymol. Wörterbuch takes this sense as developed from nautical uses, in spite of the chronology in English and French. A derivation of Middle French, French martingale from Spanish almártaga, almártiga kind of headstall put on horses over the bit to steady them when the rider dismounts (1500), prob. after an Arabic word, is to be rejected on formal as well as semantic grounds.]

## Evaluate to constants...

"Evaluate to constants" and "evaluate to constants for all values of x" are two different things.

## Not a bug...

The implicitplot issue is not really a bug: it's the loss of an undocumented feature. The help page ?implicitplot states that the endpoints a,b,c,d must evaluate to constants (and AFAIK has always stated that). Here's a work-around. Instead of implicitplot(f, x = a(y) .. b(y), y = c .. d), try this: ``` plottools[transform]((t,y) -> [a(y)*(1-t)+b(y)*t, y]) (implicitplot(subs(x=a(y)*(1-t)+b(y)*t, f), t = 0 .. 1, y = c .. d)); ```

## How about coding g to return...

How about coding g to return NULL (instead of the identity) when the condition f is not satisfied?

## DETools and DEtools...

DETools is, I think, just another name for DEtools. One of the few examples where Maple forgives a change of case. I agree that the help system could stand a lot of improvement. For example, a reasonable search feature should allow wild-cards, searching for phrases, and a choice of case-sensitive or insensitive. Or you could just put the Maple help system on-line and let people search it with Google...

## I really don't understand...

I really don't understand what you mean. I can't make sense of your worksheet. An objective function can't be a matrix, it must be a scalar. Matrices can be involved in calculating it, but in the end it must come down to a scalar expression. Also your "constraints" don't look like constraints to me. Cheers, Robert

## I really don't understand...

I really don't understand what you mean. I can't make sense of your worksheet. An objective function can't be a matrix, it must be a scalar. Matrices can be involved in calculating it, but in the end it must come down to a scalar expression. Also your "constraints" don't look like constraints to me. Cheers, Robert

## SOUND SOUND SOUND...

Maple can create .wav files with the AudioTools package, and can play them by launching an external process. See ?applications,SignalGeneration
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