MaplePrimes Questions

 

I was hoping to find a nice symbolic solution for the root of this equation:

a,c,d,k are parameters.
Unfortunately, I got an RootOf expression, which does not make sense to me. Assumptions do no help me further.

Next week, I have to present my results, but I don't know how to interpret is (the help file does not bring any relief). Is there something to say about the root? Suppose, I wanted to use side restriction on a problem? E.g., find a solution conditional on the fact that the derivative is zero. 


Clearly, in the plot it seems simple.

In one case there is a solution Maple provides: a  (a parameter)

This seems strange, because numerically there is one solution (and clearly not a).

restart

version(); interface(version)

 User Interface: 1502365
         Kernel: 1502365
        Library: 1502365

 

1502365

 

`Standard Worksheet Interface, Maple 2020.2, Windows 10, November 11 2020 Build ID 1502365`

(1)

f := proc (t) options operator, arrow; c/(1+exp(k*(t-a)))-c*(t-a)*k*exp(k*(t-a))/(1+exp(k*(t-a)))^2+d/(1+exp(-k*(t-a)))+d*(t-a)*k*exp(-k*(t-a))/(1+exp(-k*(t-a)))^2 end proc

proc (t) options operator, arrow; c/(1+exp(k*(t-a)))-c*(t-a)*k*exp(k*(t-a))/(1+exp(k*(t-a)))^2+d/(1+exp(-k*(t-a)))+d*(t-a)*k*exp(-k*(t-a))/(1+exp(-k*(t-a)))^2 end proc

(2)

assume(k > 0)

additionally(a > 0)

additionally(t > 0, t < 21)

about(a, k, t)

Originally a, renamed a~:
  is assumed to be: RealRange(Open(0),infinity)

Originally k, renamed k~:
  is assumed to be: RealRange(Open(0),infinity)

Originally t, renamed t~:
  is assumed to be: RealRange(Open(0),Open(21))
 

 

interface(showassumed = 0)

0

(3)

solve(f(t) = 0, t)

Warning, solve may be ignoring assumptions on the input variables.

 

(k*a+RootOf(-(exp(_Z))^4*d+(exp(_Z))^3*_Z*c-(exp(_Z))^3*_Z*d-(exp(_Z))^3*c-3*(exp(_Z))^3*d+2*c*_Z*(exp(_Z))^2-2*(exp(_Z))^2*_Z*d-3*c*(exp(_Z))^2-3*d*(exp(_Z))^2+c*_Z*exp(_Z)-d*_Z*exp(_Z)-3*c*exp(_Z)-d*exp(_Z)-c))/k

(4)

[allvalues(%)]

[(k*a+I*Pi+(2*I)*Pi*_Z1)/k, (k*a+RootOf(-d*(exp(_Z))^2+c*_Z*exp(_Z)-d*_Z*exp(_Z)-c*exp(_Z)-d*exp(_Z)-c))/k]

(5)

Re([op(%)][1])

a

(6)

Re([op(`%%`)][2])

(k*a+Re(RootOf(-d*(exp(_Z))^2+c*_Z*exp(_Z)-d*_Z*exp(_Z)-c*exp(_Z)-d*exp(_Z)-c)))/k

(7)

a := 'a'; b := 'b'; c := 'c'; d := 'd'; k := 'k'; t := 't'

a

 

b

 

c

 

d

 

t

(8)

Now, numerically:

b := 40; k := .3; a := 10; c := 2.8; d := -1.5

40

 

.3

 

10

 

2.8

 

-1.5

(9)

RealDomain:-solve(f(t) = 0, t)

11.02361521

(10)

plot(f(t), t = 0 .. 20, color = "DarkBlue", thickness = 2)

 

``


 

Download Please_NO_RootOf.mw

Let d and i two integers 

Put 

A := -(sum((-1)^k*binomial(i, k)*pochhammer(d*k+1, i), k = 0 .. i))/factorial(i)

and 

B := (sum((-1)^k*binomial(i+1, k)*pochhammer(d*k+1, i+1), k = 0 .. i+1))/(d*factorial(i+1))

Question: Show that A=B

Thanks!

Dear administration, I hope you all are good,why my question have been deleted? My question is a little similar to the one before, but there are still a lot of differences.I didn't do a backup which was bad.Once deleted, there is no chance of modification.

I have:

dx6PN := 9836.535181*(1 - 2.890681911*x(t) + 4*Pi*x(t)^(3/2) + 3.753665653*x(t)^2 - 37.77895388*x(t)^(5/2) + (120.1000376 - (856*ln(16*x(t)))/105)*x(t)^3 + 54.24658055*x(t)^(7/2) + (9.292369248 - 23.08463043*ln(x(t)))*x(t)^4 + (540.5708789 - 102.446*ln(x(t)))*x(t)^(9/2) + (415.3887908 + 318.8547366*ln(x(t)))*x(t)^5 + (1549.709468 - 384.6723254*ln(x(t)))*x(t)^(11/2) + (2172.892557 + 407.4405529*ln(x(t)) + 33.2307*ln(x(t))^2)*x(t)^6)*x(t)^5

Ms := 0.0003214719000

xlow := 0.04672277118

tin := 4.125604512

I want to solve the following for t>tin to obtain xphi. I then want to plot xphi over the range tin to tin+1:

diff(x(t), t) = dx6PN, diff(xphi(t), t) = (x(t)^(3/2))/Ms, x(0) = xlow, xphi(tin) = 0

I could use some help.

Hi,

Is there a possibility of aligning choices in a horizontal manner?

Thanks

QuizzTest1.mw

Given two lists say of same number of elements 

 

A = [1,0,3,4,5,5]

B=[0,1,2,6,3,6]

How to write a code find number of elements of A which are greater than the number of elements of B index wise in the above 1>0,3>2,5>3 so three elements. 

And also the number of elements of B greater than the number of elements A index wise

1>0,6>4,6>4.hence 3 elements

 

Index wise compared to note 

 

Kind help 

 

Hi everybody, I want to find 

the second-order derivative according to alpha. Since the computer could not calculate in this way, I took the derivative twice in a row.

assume(alpha <= 1)

additionally(0 < alpha)

then output is

again using the fracdiff 

then output is 

but I want to see

after the last command. Should alpha be defined specifically for this?

I know that the angle between two vectors u = (2, 1, 1) and v = (9, -1, 4) equal to 30 degree. How to find the some options of two vectors u = (a, b, c) and v = (x, y, z), where a, b, c, x, y, z are six integer numbers so that  the angle between two vectors u and v equal to 30 degree?

Bagaimana cara menemukan domain f (x) = x 2 -x + 3?

Dan bagaimana saya bisa menemukan rentang y = f (x) -g (x) jika fungsinya diketahui f (x) = x 2 -x + 3 dan g (x) = 3x-5?

Given a Graph say G with its adjacency matrix say. 

Consider a edge uv in the graph say 

how to find the number of vertices of 

Case1 : The number of vertices of graph G whose distance to the vertex v is smaller than the distance to the vertex u.

Case 2:  The  number of vertices of graph G whose distance to the vertex u
is smaller than the distance to the vertex v.

To u is adjacent to V that is uv is a edge here. 

I installed Maple 2021 on windows 10. And wanted to try it to see if the hangs I used to have are fixed now.

First I noticed that Physics package does not come pre-installed with Maple 2021, which is little strange. I would have expected Maple 2021 to come with latest Physics version.

Because when I did Physics:-Version() it says "`The "Physics Updates" package is not installed`"

Then I typed  Physics:-Version(latest) to install it, it gives error

Error, (in Physics:-Version) unable to determine the Physics Updates version, could you please report the problem to support@maplesoft.com
 

 

I remember something similar in earlier version of Maple but can't find or remember where that post now.

May be Physics needs to be updated at Maple site to work with Maple 2021? I am asking, because Latex() does not work without Physics installed.

Edit:

I think in Maple 2021, latex() now is the same as the earlier Latex() command from Physics? I remember a post saying this now. Since I see now latex() have different help page from old latex() help page.

So may be that is why Latex() did not work. I can easily change this in my code to change it to use latex() instead of Latex() in this case. 

Windows 10

 

 

 

Hello!

I have a difficulty with a function used in procedure. The procedure uses a multivariable function and if the specific choice of the function is not made the procedure seems to give proper result, but In case I make a specific choice of the function and then try use this procedure gives me incorrect result.

To be more exact I use Physics package (there is a need to calcute combinations of covariant derivates ). The calculations are performed in a curved space with a defined metric.

So here is the procedure:

SD2 := proc (psi) SumOverRepeatedIndices(g_[`~kappa`, `~lambda`]*(d_[kappa](d_[lambda](psi(X)))-Christoffel[`~sigma`, kappa, lambda]*d_[sigma](psi(X))))^2-SumOverRepeatedIndices(g_[`~kappa`, `~rho`]*(d_[kappa](d_[lambda](psi(X)))-Christoffel[`~sigma`, kappa, lambda]*d_[sigma](psi(X)))*g_[`~lambda`, `~tau`]*(d_[rho](d_[tau](psi(X)))-Christoffel[`~gamma`, rho, tau]*d_[gamma](psi(X)))) end proc;

If I turn to the procedure :

SD2(psi);

the result is  correct.

But  then I specify a psi function:

psi:=(t,r,x,y,z)->chi(r)+q*t;(here q is supposed to be a constant)

and turn to the procedure once again:

SD2(psi);

It gives me a wrong result.

I don't know what is the reason.

Thank you.

 

 

How do you print [0,infinity) in Maple 13 like
?

RealRange does not seem to work.


Thank you!

mapleatha

This has always made me wonder everytime I type it.

The first command I always type on a new worksheet is restart.  I don't think I have never done this. 

Is there a reason it needs to be manually entered and how many people DO NOT start a worksheet with a restart?   

Is there a reason to not make this automatic with initial loading of a worksheet?
 

Thanks,

Bill

The plot command below results in the following graph:

However, I want the x-axis to go from 0..24 and the y-axis from 0..100. I can adjust the shafts temporarily via Axes-Properties so that I get the following plot:

However, as soon as I recalculate the plot command, I get back the original plot. Is there any parameter in the plot command where I can set x-min, x-max, ymin, ymax?

Regards,

Christer

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