I have a table whose indices and entries are strings, as in:

    T := table(["green" = "gruen", "red" = "rot", "blue" = "blau"]);

Thus, T["green"] evaluates to "gruen" but T["asdf"] evaluates to T"asdf".

What is a good way to detect that "green" is a predefined index into the table but "asdf" is not?  I do it in a somewhat clumsy way, as in:

> has("green", [indices(T, 'nolist')]);
        true

> has("asdf", [indices(T, 'nolist')]);
        false

I suspect that there ought to be a less elaborate way of doing that.

I'm currently having some difficulties in solving a system of differential equations numerically.

This is my code.

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Dear Friends:

I am currently working on a calculation for phase velocity of acoustic waves and don’t get along.  

My equation has the following form:

equ := tan( (31 / 20000) * sqrt( -9610000/c^2 + 1) / Pi) / tan((961/1260000) * sqrt( -39690000/c^2 + 1)/ P i) = -(1191640000/63)*sqrt(-9610000/c^2 + 1)*sqrt (-39690000/c^2 + 1)/ (c^2*(19220000/c^2 - 1)^2)

Using ‘sol = solve(equ,c)’ returns

sol := 96100* RootOf(1 + (400000000 * Pi^2 * RootOf(40320000000000000000 * Pi^4 * tan(_Z)*_Z^4256000000000000 * Pi^3 * csgn(_Z) * _Z^3 * tan((1/157500) * sqrt(24806250000 * Pi^2 * _Z^2 - 45167) / Pi) * sqrt(24806250000 * Pi^2 * _Z^2 - 45167) -96868800000000 * Pi^2 * tan(_Z) * _Z^2 + 615040000 * Pi * csgn(_Z) * _Z * tan((1/157500) * sqrt(24806250000 * Pi^2 * _Z^2 - 45167) / Pi ) * sqrt(24806250000 * Pi^2 * _Z^2 - 45167)+58181823 * tan(_Z))^2 - 961)* _Z^2)

c should be in a range of 13,000.

Two questions:

1) How can I deal with _Z?

2) Any suggestion how I can calculate ‘c’? Maybe numerical?

I am relative new in maple…

Many thanks!

Alex

Hi,

Might be a silly question but how do I preview/display the expression I type instead of maple automatically solving it.

For example, If I type in '1+1' in wolfram, it displays 'input: '1+1'' right below it.

I would like to do this in maple but cant seem to figure it out.

Hopefully that made some sense.

Cheers and thanks! 

Int(piecewise(t < T1, exp((1/2)*t*(1+2*I-I*sqrt(3))), t < T2, -1000*exp((1/2)*t*(1+2*I-I*sqrt(3)))*(-1/1000+T1-t), T2 <= t, -1000*exp((1/2)*t*(1+2*I-I*sqrt(3)))*(-1/1000-T2+T1)), t)

The help of maple software is not so clear , and I cant understand the exact way which leads to exporting a matrix from maple to matlab. more precisely how I can link between maple and matlab .

would you please with an example show me the rule.

I just wanted to ask whether one can get out of the expansion

(D-f(x))@@2(g)(x)=(D@@2)(g)(x)-(D((f(x))(g)))(x)-((f(x))(D(g)-(f(x))(g)))(x)

the intended result

(D@@2)(g)(x)-D(f*g)(x)-f(x)*D(g)(x)+f(x)^2*g(x)

Can we rotate 3d text in Maple like this shown here?

http://mathematica.stackexchange.com/questions/25065/rotating-3d-text

Let us consider the definite integral

J:=int(abs(x-(-x^5+1)^(1/5)), x = 0 .. 1);

Maple fails with it, Mathematica 10.1 finds it in terms of  special functions. Let us look at the integrand:
plot(x-(-x^5+1)^(1/5), x = 0 .. 1);

We see the expression under the modulus changes its sign at the unique point of RealRange(0,1). Therefore

solve(x-(-x^5+1)^(1/5));

Then

J:= int(-x+(-x^5+1)^(1/5), x = 0 .. (1/2)*2^(4/5))+int(x-(-x^5+1)^(1/5), x = (1/2)*2^(4/5) .. 1);

which outputs a complicated expression

(1/8)*2^(4/5)*(4*hypergeom([-1/5, 1/5], [6/5], 1/2)-2^(4/5))+(1/2)*2^(4/5)*((1/2)*2^(1/5)-(1/4)*2^(4/5))-(1/25)*Pi*csc((1/5)*Pi)*(-(25/2)*sin((1/5)*Pi)*GAMMA(4/5)*2^(4/5)*hypergeom([-1/5, 1/5], [6/5], 1/2)/Pi+(5/4)*sec((3/10)*Pi)*cos((1/10)*Pi)*2^(3/5)*Pi^(1/2)*csc((3/10)*Pi)/GAMMA(7/10))/GAMMA(4/5).

At the same time we have

int(abs(x-(-x^5+1)^(1/5)), x = 0 .. 1, numeric);

                          0.5000000000

How to obtain 1/2 symbolically?

I am trying to integrate product of exp(t+s) and a piecewise polynomial but the result can not be read and not usefull. also I used numerical integration function "Quadrature" but the result did not change.

error.mwerror.mw

Hi, I'm having a problem regarding this equation:
                                                           sum(v(i), i = 1 .. 28)

where, v is a Data Table created under the Components Tab with 28 Rows, and 1 Column.

I keep on getting an error of: 

                                                     Error, unsupported type of index, i

I didn't use or declare 'i' in any part of the program.

Thank you for your help! 

On a related post here, I have posted some screen shots for fun. Today is a special day for me in particular, because I passed my PhD viva with minor corrections! If you look colsely on the date, by coincidence, it was TWO years ago exactly. So I feel like I maybe 'update' the old post with a bit more, to make it V2.

So here comes the new screent shots: (Bear with me for now, I will post some actual content about how I feel when using Maple later.)

Alright, enough with the screent shots. If you click to see the big picture, you would notice that I have managed to get a complete sets of Maple versions from Maple V to Maple 2015!

===============================================

I am originally from Shanghai and I have always done well in Maths and science. I first heard about Maple in 2004 from a Maths teacher. He introduced me to this software. I played just a couple of times with Maple 6 on his computer, to get a first impression. At that time, all I could say was, hmmm insteresting.

In 2006, I went to UK for a foundation course. That was the first time I was actually taught how to use Maple 9.5. So I had access to it on the university computers. I discovered a lot about Maple and used it for ALL my Maths homeworks. Yes, I am lazy. I hope that Maple can do everything!

Then I got fascinated with Maple. Unfortunately, Maple was not taught in the undergraduate course. But there are materials for self-learning. By that time, I had become quite good with most of the contents in those materials. So I went look for other things to try. I went to ask my foundation course classmates, to see if they have anything on Maple and if they needed the help. One of them was at Imperial College and the questions were a bit chanlleging (finally!). That was the time I first met MaplePrimes! Hello, how have you been?

After that I have never stopped using Maple or Maple Primes. I may have been quite on the forum, but I was there. My PhD research rely hugely on the ability to compute the symbolic rank of certain matrices as well as the ability to simplifiying complicated expressions using siderules.

I do not want to talk too much about the technical details when using Maple. But I do

THANK Maple and it creators, developers and all relavent staff around the globe.

THANK Maple Primes and all its users. Some users have been particulary helpful!

Lastly, I dont have any other words to say other than this:

It's been really fun and enjoyable. Thanks!