When experimenting with Maple 2016.1, I found several issues. One I have seen on MaplePrimes before (regarding "Error, incorrect syntax in parse: `;` unexpected (near 4th character of parsed string)" when evaluating an integral, for example, or trying to plot something), but another I have not seen - it may be related to the previous issue. Below is a document that contains some of the various errors I found. What is going on? It evaluates certain things correctly, but, in the integral, it treats "x^2" like a whole new variable (the integral of x^2 with respect to x from 0 to 2 it says is 2x^2, not 8/3). The same thing results in trying to plot x^2 (not shown), giving the same error if I were to say something like "plot(t,x=0..2)" - it cannot determine the plotting variable.
 

Download bad_maple.mw 

Any ideas? Are the two things (the Error, incorrect syntax in parse: `;` unexpected (near 4th character of parsed string) message and the bad integral value) related?

How do I create a function from dsolve() result?

For example, dsolve() outputs:

u(t) = u₀e^{a t}

then I would like to create function:

u := t → u₀e^{a t}

but I want to do it using dsolve() output, not typing it manually. Thanks.

How I can write a procedure with Maple 18 that it receives function f(x) and x=a as inputs, 
then compute f'(a) and shows in output these 2 cases:

1) value f'(a)
2) curves f(x) ,y=f'(a)*(x-a)+f(a) and also the point (a,f'(a)) in a system ?

When Maple 2016 hit the road, I finally relegated my printed Mollier charts and steam tables to a filing cabinet, and moved my carefully-curated spreadsheets of refrigerant properties to a distant part of my hard drive. The new thermophysical data engine rendered those obsolete.

Other than making my desk tidier, what I find exciting is that I can compute with fluid properties in a tool that has numerical integrators, ODE solvers, optimizers, programmatic visualisation and more.

Here are several small examples that demonstrate how you can use fluid properties with Maple’s math and visualization tools (this worksheet contains the complete examples).

Work Done in Compressing a Gas

The work done (per unit mass) in compressing a fluid at constant temperature is

where V₁ and V₂ are specific volumes and p is pressure.

You need a relationship between pressure and specific volume (either theoretical or experimental) to calculate the work done.

Assuming the ideal gas law, the work done becomes

where R is the ideal gas constant, T is the temperature (in K) and M is the molecular mass (in kg mol^-1), and V is the volume.

 Ideal gas constant

Molecular mass of propane

Hence the work done predicted by the Ideal Gas Law is

Let’s now use real fluid properties instead and numerical integrators to compute the work done.

Here, the work done predicted with the Ideal Gas Law and real fluid properties is similar. This isn’t, however, always the case for all gases (try experimenting with ammonia – its strong intermolecular forces result in non-ideal behavior).

Minimum Specific Heat Capacity of Water

The specific heat capacity of water varies with temperature like so.

Let's find the temperature at which the specific heat capacity of water is the lowest.

The lowest specific heat capacity occurs at 309.4 K; this is the temperature at which water requires the least energy to raise or lower its temperature.

Incidentally, this isn’t that far from the standard human body temperature of 310.1 K (given that the human body is largely water, one might hazard a guess why we have evolved to maintain this temperature).

Temperature-Entropy Plot for Water

Maple 2016 generates pressure-enthalpy-temperature charts and psychrometric charts out of the box. However, you can create your own customized thermodynamic visualizations.

This, for example, is a temperature-entropy chart for water, together with the two-phase vapor dome (the worksheet contains the code to generate this plot).

I'm also working on a lumped-parameter heat exchanger model with fluid properties (and hence heat transfer coefficients) that change with temperature. That'll be more complex than these simple examples, and will use Maple's numeric ODE solver.

I have a system of 16 polynomial equations in 15 variables. Independently I know there is at least a one parameter familiy of solutions to this system, so there is reason to think at least two of the equations are redundent. I would like to use Maple to decipher which of the equations are redundent, but I am unsure how to proceed.

So far I have looked at the Groebner package, and it seems like the Reduce and InterReduce commands will be useful. Say I call the set of 16 polynomials X and define a lexicographical order T on the variables. I then ask maple to compute

Reduce(X,X,T)

and receive a list with 7 zeroes and 9 polynomials. What exactly is this telling me? Does this mean that maple has used polynomial division and found that 7 of the equations are redundent?

Thanks for your help!

the expression

sN=a1+a2+...+aN

for k from 1 to N do

psum=psum+a(n);

end do;

s[k]:=psum;

end do:

how do we transform this using only one loop?

thanks

minimize((x+y)^2+cos(y)^2, x=-4..4, y=-2..2);  # cos(2)^2    should be 0
minimize((x+y)^2+cos(y), x=-4..4, y=-4..4);      
   Error, (in unknown) mapped procedure in `ormap' must return true or false
minimize((x+y)^2+cos(y));                                   # infinity   ?!  should be -1

Edited. Corrected second example

Hello there! Maple 2016.1 sometimes gets crasy about parsing input strings. I managed to capture this behaviour in the attached file. It looks like below. I am not sure what exactly triggers it. It just starts happening all of a sudden. What might be the cause...? 

Download test.mw

I have the following command （credit to @Carl Love ), this command will do certain bit shifting with the next block, and the last block will shift with the first block. 

B:= Matrix([[0,0,1,1,0,0,1], [0,0,1,1,1,0,0],[0,1,0,1,0,1,0], [1,0,0,1,1,1,0]]):
Bnew:= copy(B):
Bnew[[4,1,2,3], 3..5]:= B[.., 3..5]:
Bnew; 

May i know any command can help to reverse the shifting position between the block？

for example,

original block  [0,0,1,1,0,0,1], [0,0,1,1,1,0,0],[0,1,0,1,0,1,0], [1,0,0,1,1,1,0]

i need to shift the 3..5 position of block 1 and change to the 5..3 position of block 2. 

Example:

After shifting, 

Bnew=[0,0,1,1,1,0,1],[0,0,0,1,0,0,0],[0,1,1,1,0,1,0],[1,0,0,1,1,1,0]

Any command can help to solve? thank you in advance.

May I know any command can help to random selected a position in a group of bit number then flip that number but with condition after convert to bytes the number cannot be more than 7?

For example,

I have integer 3, i convert to binary become 0000011

then i need a command to random select a position to flip and only one bit can be flipped.

After that the group of flipped number will convert back to decimal, but total value cannot more than 7? any command can solve?  Thank you. 

Hi Maple Primes

I have this parabola -

y2:=6z^2 +z+244;

x2:=9z^2+3z+367;

I use the eliminate command to write without z;

c:=eliminate([y=y2,x=x2],z);

Then I have the expression

e2 = 4x^2-12xy+9y^2-7x+9y+369.

My questions is, what integer values for x and y are on the curve e2?

I think the answer may be exactly when z is an integer.

How could I determine this given only e2?

Regards,
Matt

Hello,

How can I get the minimum point of (sin(x+y))

plot3d(sin(x+y), x=-1..1, y=-1..1);

Hi,

I would like to plot a cone where I can change the vertex angle directly. I would also to be able to change the size of the cone. I have tried:

cone([r*cos(phi)*sin(theta), r*sin(phi)*sin(theta), r*cos(theta)], phi = 0 .. 2*Pi, r = 0 .. 1, theta = (1/6)*Pi, coords = spherical)

but this gives me the following error:

Error, (in plot3d) unexpected options: [[r*cos(phi)*sin(theta), r*sin(phi)*sin(theta), r*cos(theta)], phi = 0 .. 2*Pi, r = 0 .. 1, theta = (1/6)*Pi]

Thanks!

Hello

I would like to know if it is possible to change the color for the result from blue to black or red. Maybe by editing the text that state the colors.

And the same goes for the color palette, can I make my own colors in the color palette text. It should work by default.

Regards

Heide

Hi everybody;

In the following attached file, I am trying to solve a system of nonlinear equations with one equality constraint. I have 9 equations and 9 unknowns. Attached file has composed of 3 main parts, first is input data, second is the 9 nonlinear equations from E_1 to E_9 and finally third part is constraint equation called C_1. My unknowns are "phi, theta, p, q, r, T, L, M and N". My question is that: Can Maple solve this problem?? Is there any solution to this problem or I have to change input data?? If Maple can solve this problem, how can I do that?? 

I appreciate your help in advance.

NL.mw