MaplePrimes Questions

I am using Scientific notations and it constatly reminds me of the units and conversion challenges of using Maple.  I am using 2018 and am an engineer where units are our life blood for calculations.

 

Ive attached the file in ref where the constants shows J/Kg-mol   but outputs in a converted base unit of m^2 kg / s^2 mol K.  This modifies the value normally used by tables or other references as verification (often without units except in a column header)

 

The real problem is without units the caculated value 34.52 (or 0.03452) is meaningless when the real value has to be 287.05 if used without units or has correction applied within the SW internally.   

Units is my singular frustration with Maple as a really useful tool.  2018 moved this forward in so many ways which is very benficial.  I am really wondering if it may be how I'm setting the session up, or it is what it is.

Units_conversion_issue.mw

 

Trying to read the docs, I find a lot of information in section that appear closed, and I'm supposed to move my hand from the keyboard to the mouse to bounce a laser off my desk to click triangles on the screen to make the information I need visible. Sometimes when I click a triangle, it opens the section and lets me read the docs. Other times I click a triangle, it does nothing, so I click again, and eventually it works. This process is unpleasant. Is there any way predictable way to view the docs, or just click triangles and hope?

New user. Start a new "Worksheet Mode". Type "3" and press Enter. Maple evaluates it to 3. Decide I want to add a section-heading above the original first line. Head into the docs and emerge several hours later still not having found any way to add a section-heading above the original first line. How did I lose so many hours of time on something so basic? Where was this routine task documented?

Hi. I wrote a command for finding second derivative.

#secondderiv test of f(x,y)
f:=x^2+2*x*y+2*y^3:
Gradient(f,[x,y]);
soln:=solve(Equate(Gradient(f,[x,y]),<0,0>));
H:=hessian(f,[x,y]);
seq([subs(soln[k],eval(H)),det(subs(soln[k],eval(H)))],k=1..nops(op(soln)))

Everything runs fine ... except if I change the function f to
f:=x^2+2*x*y+2*y^2
Then I get error :
Error, invalid input: nops expects 1 argument, but received 2

I sort of understand the error, when there is a single solution
{x=0,y=0} , then the op removes the parentheses to get x=0, y=0
which is now two arguments, and nops requires one argument.
I tried to use  nops(op({soln} ) , but that is not the correct approach
since it overcounts. Also it throws an error if change back f to the original expression.


 

 

Hello,

I have an implicit function and I have plotted the graph of the same in maple 18 worksheet. Now I would like to export the data of the same graph into an excel file so that I can use it further. Kindly provide the solution and if some kind of example is provided I'll be highly grateful to you.

Thanks in advance

when i evaluate integration and my result s are HFloat what does it mean ?

how to avoid it ?

and how to distribute integration when the expand command doesnt work?
 

Can someone please explain to me why i would be getting the error that i do not have permission to read a text file, when i can clearly open that text file under the same account.

 


 

``

first := readline("infile.text")

Error, (in readline) permission denied: no read access (infile.text)

 

``


 

Download 111.mw

Hi

I need to express some discrete functions with domain in the natural numbers.

Is there a command like the 'AllSolutions' which is used for int?

As an example, how we can express all possible values of first derivative of chebyshev polynomial for various orders in terms of a piecewise function at origin ?

The following commands do not return a suitable answer, in this case!

f:=diff(ChebyshevT(n, r), r):

g:=simplify(eval(f, r = 0), symbolic) assuming(n::integer);

`assuming`([convert(g, piecewise, n)], [n::integer]);

Hello people in mapleprimes,

I installed maple 2018 Japanese version.
And, with solve(x^2-1,x), its solution is expressed as _EXPSEQ(1, -1)

I know this expression is an internal represantation.
How can I have maple answer as 1, -1?

Thanks in advance.

Addition: my pc is mac osx 10.13.6.
 

 

 

Hello,

I'm trying to solve  inverse trigonometric equation:

EQ := sqrt(3)*arctan(x/sqrt(3))-arctan(x) = 1;

sol := solve(EQ, {x});

#sol := {x = sqrt(3)*tan(RootOf(-tan(sqrt(3)*_Z-1)*sqrt(3)+3*tan(_Z)))}

evalf(sol);

#{x = 13.24164497} OK. one Real solution.

sol2 := evalf(allvalues(sol));

#sol2 := {x = -.1141310781-1.108044977*I}, {x = -.1141310781+1.108044977*I}, # {x = 1.142681884}, {x #= -2.379974990}, {x = 13.24164497}

Check:

seq(evalf(eval(EQ, sol2[k])), k = 1 .. nops([sol2]));

#.99999999991340592650+1.61960960*10^(-11)*I = 1., .99999999991340592650-#1.61960960*10^(-11)*I = 1., .15821278548775934290 = 1., -.4580182246463005988 = 1., #.9999999996233630663 = 1.

1.Can someone explain to me where did Maple find these Additional roots like: {x = 1.142681884}, {x = -2.379974990}?

2.It's a Bug or normal behavior ?

 

I have three questions

1:= If I have summation over i from 0 to 100 how do I prevent maple from unpacking the sum and set it like it is?

2:= Does the comand evalf give me an imaginary evaluation if we apply it in a sum and how do I avoid that?

3:= For infinite sum, Maple evaluates it with term hyper geometry and can't after that evaluate the diffrentation how do I prevent that?

Good morning, I'm trying to solve this very simple problem : plot a graph starting from the origin. The problem is that the x_axis is located at the lower value of my function, but i want it to go through the point (0,0). Let's see this example:

plot(piecewise( x<5, 100, x>5,200), x=0..10); As you can se the X-axis passes through y=100.

Now with this option I obtain:

plot(piecewise( x<5, 100, x>5,200), x=0..10, y=0..200); 

The problem is taht I need to specify the upper bound of the range for each function (200). Is there an automatic way? Any help is appreciated.


 

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