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C_R

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7 years, 53 days
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How to revert ("unapply") a fu...

C_R 4069 Maple 2026
composition unapply
September 18 2026
1 6

How to revert ("unapply") a function composition application?
Example:

`@`(ln, sinh)

`@`(ln, sinh)

 (1)

apply(`@`(ln, sinh), x)

ln(sinh(x))

 (2)

Unapply does not do the opposite of what apply does

unapply(ln(sinh(x)), x)

proc (x) options operator, arrow; ln(sinh(x)) end proc

 (3)

What I am instered in: revert/undo the apply operation leading to(2) and returning the corresponding function composition of (1).

Maybe there is a convert function that I have overlooked.NULL

Download revert_application_of_function_composition.mw

Integrating the derivative of tanh...

C_R 4069 Maple 2026
integration tanh
September 03 2026
1 7

I could not figure out why Maple does not return tanh. Instead a complex valued function for real arguments is returned. This is not recent. I tried down to Maple 2020.  Is that correct?

 

> 

D(tanh);
plot(%)

-tanh^2+1

  

 
> 

int(D(tanh)(x),x);# I expected tanh
plot(%);# ok, no plot for real valued x

x+tanh(x)+(1/2)*ln(tanh(x)-1)-(1/2)*ln(tanh(x)+1)

  

Warning, unable to evaluate the function to numeric values in the region; complex values were detected

  
> 

int(D(tanh)(x),x=0..infinity);# this result seems to be known in advance and fits to the above plot

1

 (1)
> 

int(D(tanh)(x),x=a..b);
eval(%,[a=0,b=infinity]);# I expected 1 from (1)
eval(%%,[a=0,b=50.]);# retruns complex for small values

-a-tanh(a)-(1/2)*ln(tanh(a)-1)+(1/2)*ln(tanh(a)+1)+b+tanh(b)+(1/2)*ln(tanh(b)-1)-(1/2)*ln(tanh(b)+1)

  

Error, (in ln) numeric exception: division by zero

  

-Float(infinity)-((1/2)*I)*Pi

 (2)
> 

evalf(int(D(tanh)(x),x=0..50))

1.000000000

 (3)

Let's try integrating the identical expression sech^2

 

tanh(x)

 (4)
> 

is((sech^2=1-tanh^2)(x));# check identity

true

 (5)
> 

int(sech(x)^2,x);# what I expected

tanh(x)

 (6)

Download Integrating_D_tanh.mw

How to deal with this AI prompt error...

C_R 4069 Maple 2026
ai
August 27 2026
0 3

After starting Maple

I then tried simpler prompts like "Hello", simplify(x),...

For all prompts I get the same error message.
I am not a frequent AI user but this is the first time I see that.
Has anybody else experienced the same?

Can someone send me a prompt that should work?

(Model type was Simple.)

Update:

It seems that this error occurs, when a second instance of Maple 2026.1 is started and AI is consulted in this instance. 

Why is D not efffective on (ln@cosh)...

C_R 4069 Maple
composition differentiation functional-operator
August 27 2026
2 1

To D(ln@cosh) I have to add an argument to make it work (Edit: no output returned):

D(ln@cosh)(x);
                            sinh(x)
                            -------
                            cosh(x)

According to ?D I expected output according to this

Interupting Maple not working...

C_R 4069 Maple 2026
interrupt gui
August 16 2026
0 14

I am only occasionally using Maple versions with the new ribon user interface and noticed about 2 weeks ago that I cannot interrupt for loops under these interfaces. For example this one

for i to 1000 do
    i^i;
end do

I re-run the code today (after installing windows updates) and could interrupt before the screen was filled with output but not after executing the code a second time (without restart).

Is that reproducible on other installations?

Are there other commands that cannot be interrupted? 
If that is known, are there workarounds?

Update:
I have restarted Maple and have two worksheets open with the same code. I can repeatedly interrupt in one worksheet but not in other

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