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MaplePrimes Questions

Solving for intersect of two circles...

Asked by: Ronan 1341
solve signum circle
October 28 2023
2  1

If if solve for two circles intersecting the general solution conteint a factor of (xc1-xc2) i.e. x co-ors of the circle centres in both numerator and denominator. So the solution fails if they are equal i.e circles vertically aligned.
I can get arount the problem using  "RealDomain" but that introduces Signum which I dont like and is much slower to solve. I substitued out substitued signum out signum(xc1-xc2)=1. Works.

Just looking for is neater solution approach.
 

restart

NULL

eq1 := (x-xc1)^2+(y-yc1)^2 = R1^2

(x-xc1)^2+(y-yc1)^2 = R1^2

 (1)

eq2 := (x-xc2)^2+(y-yc2)^2 = R2^2

(x-xc2)^2+(y-yc2)^2 = R2^2

 (2)

eq3 := (xc1-xc2)^2-(yc1-yc2)^2 < (R1+R2)^2

(xc1-xc2)^2-(yc1-yc2)^2 < (R1+R2)^2

 (3)

Sol1 := `~`[simplify](solve({eq1, eq2}, [x, y], explicit))[]

[x = (1/2)*((-yc1+yc2)*(-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)-(xc1-xc2)*(-xc1^3+xc1^2*xc2+(R1^2-R2^2+xc2^2-yc1^2+2*yc1*yc2-yc2^2)*xc1-xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2)))/((xc1^2-2*xc1*xc2+xc2^2+(yc1-yc2)^2)*(xc1-xc2)), y = ((-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+yc1^3-yc1^2*yc2+(-R1^2+R2^2+xc1^2-2*xc1*xc2+xc2^2-yc2^2)*yc1+yc2^3+(R1^2-R2^2+xc1^2-2*xc1*xc2+xc2^2)*yc2)/(2*yc1^2-4*yc1*yc2+2*yc2^2+2*(xc1-xc2)^2)], [x = (1/2)*((yc1-yc2)*(-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)-(xc1-xc2)*(-xc1^3+xc1^2*xc2+(R1^2-R2^2+xc2^2-yc1^2+2*yc1*yc2-yc2^2)*xc1-xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2)))/((xc1^2-2*xc1*xc2+xc2^2+(yc1-yc2)^2)*(xc1-xc2)), y = (-(-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+yc1^3-yc1^2*yc2+(-R1^2+R2^2+xc1^2-2*xc1*xc2+xc2^2-yc2^2)*yc1+yc2^3+(R1^2-R2^2+xc1^2-2*xc1*xc2+xc2^2)*yc2)/(2*yc1^2-4*yc1*yc2+2*yc2^2+2*(xc1-xc2)^2)]

 (4)

eval(Sol1[1], [R1 = 85, R2 = 30, xc2 = 200, yc2 = 144.85, xc1 = 130, yc1 = 95.7071])

[x = 178.3493912, y = 165.6165872]

 (5)

eval(Sol1[2], [R1 = 85, R2 = 30, xc2 = 200, yc2 = 144.85, xc1 = 130, yc1 = 95.7071])

[x = 212.1767210, y = 117.4323513]

 (6)

NULL

NULL

NULL

NULL

Sol2 := `assuming`([`~`[simplify](solve({eq1, eq2}, [x, y], explicit))[]], [eq3])

[x = (1/2)*((-yc1+yc2)*(-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)-(xc1-xc2)*(-xc1^3+xc1^2*xc2+(R1^2-R2^2+xc2^2-yc1^2+2*yc1*yc2-yc2^2)*xc1-xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2)))/((xc1^2-2*xc1*xc2+xc2^2+(yc1-yc2)^2)*(xc1-xc2)), y = ((-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+yc1^3-yc1^2*yc2+(-R1^2+R2^2+xc1^2-2*xc1*xc2+xc2^2-yc2^2)*yc1+yc2^3+(R1^2-R2^2+xc1^2-2*xc1*xc2+xc2^2)*yc2)/(2*yc1^2-4*yc1*yc2+2*yc2^2+2*(xc1-xc2)^2)], [x = (1/2)*((yc1-yc2)*(-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)-(xc1-xc2)*(-xc1^3+xc1^2*xc2+(R1^2-R2^2+xc2^2-yc1^2+2*yc1*yc2-yc2^2)*xc1-xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2)))/((xc1^2-2*xc1*xc2+xc2^2+(yc1-yc2)^2)*(xc1-xc2)), y = (-(-(xc1-xc2)^2*(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+yc1^3-yc1^2*yc2+(-R1^2+R2^2+xc1^2-2*xc1*xc2+xc2^2-yc2^2)*yc1+yc2^3+(R1^2-R2^2+xc1^2-2*xc1*xc2+xc2^2)*yc2)/(2*yc1^2-4*yc1*yc2+2*yc2^2+2*(xc1-xc2)^2)]

 (7)

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

with(RealDomain)

Sol3 := `~`[simplify](solve({eq1, eq2}, [x, y], explicit))[]

[x = (-(yc1-yc2)*signum(xc1-xc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+xc1^3-xc1^2*xc2+(-R1^2+R2^2-xc2^2+yc1^2-2*yc1*yc2+yc2^2)*xc1+xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2), y = (signum(xc1-xc2)*(xc1-xc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+(yc1+yc2)*xc1^2-2*xc2*(yc1+yc2)*xc1+(yc1+yc2)*xc2^2-(yc1-yc2)*(R1^2-R2^2-yc1^2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2)], [x = ((yc1-yc2)*signum(xc1-xc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+xc1^3-xc1^2*xc2+(-R1^2+R2^2-xc2^2+yc1^2-2*yc1*yc2+yc2^2)*xc1+xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2), y = (-signum(xc1-xc2)*(xc1-xc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+(yc1+yc2)*xc1^2-2*xc2*(yc1+yc2)*xc1+(yc1+yc2)*xc2^2-(yc1-yc2)*(R1^2-R2^2-yc1^2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2)]

 (8)

eval(Sol3[1], [R1 = 85, R2 = 30, xc2 = 200, yc2 = 144.85, xc1 = 130, yc1 = 95.7071])

[x = 178.3493912, y = 165.6165871]

 (9)

eval(Sol3[2], [R1 = 85, R2 = 30, xc2 = 200, yc2 = 144.85, xc1 = 130, yc1 = 95.7071])

[x = 212.1767209, y = 117.4323512]

 (10)

Sol3a := subs(signum(xc1-xc2) = 1, Sol3[1])

[x = (-(yc1-yc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+xc1^3-xc1^2*xc2+(-R1^2+R2^2-xc2^2+yc1^2-2*yc1*yc2+yc2^2)*xc1+xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2), y = ((xc1-xc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+(yc1+yc2)*xc1^2-2*xc2*(yc1+yc2)*xc1+(yc1+yc2)*xc2^2-(yc1-yc2)*(R1^2-R2^2-yc1^2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2)]

 (11)

Sol3b := subs(signum(xc1-xc2) = 1, Sol3[2])

[x = ((yc1-yc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+xc1^3-xc1^2*xc2+(-R1^2+R2^2-xc2^2+yc1^2-2*yc1*yc2+yc2^2)*xc1+xc2*(R1^2-R2^2+xc2^2+yc1^2-2*yc1*yc2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2), y = (-(xc1-xc2)*(-(-xc1^2+2*xc1*xc2-xc2^2+(R1-R2+yc1-yc2)*(R1-R2-yc1+yc2))*(-xc1^2+2*xc1*xc2-xc2^2+(R1+R2+yc1-yc2)*(R1+R2-yc1+yc2)))^(1/2)+(yc1+yc2)*xc1^2-2*xc2*(yc1+yc2)*xc1+(yc1+yc2)*xc2^2-(yc1-yc2)*(R1^2-R2^2-yc1^2+yc2^2))/(2*xc1^2-4*xc1*xc2+2*xc2^2+2*(yc1-yc2)^2)]

 (12)

eval(Sol3a, [R1 = 85, R2 = 30, xc2 = 200, yc2 = 144.85, xc1 = 130, yc1 = 95.7071])

[x = 212.1767209, y = 117.4323512]

 (13)

eval(Sol3b, [R1 = 85, R2 = 30, xc2 = 200, yc2 = 144.85, xc1 = 130, yc1 = 95.7071])

[x = 178.3493912, y = 165.6165871]

 (14)

NULL


 

Download 28-10-28_Q_Circles_Intersect.mw

 

Corrupted maple document. How can I recover this d...

Asked by: kris 10
worksheet corruption
October 28 2023
2  1

It seems like my maple document has been corrupted. When I tri to open the document I'm met with an error message "There were problems during the loading process. Your worksheet may be incomplete."

I have spent a great amount of time in this document, so if there was a way to recover it, that would be fantastic.

Thanks!

Download prac_exam_ece4179.mw

Unsolvable integral in Maple...

Asked by: Sky-Bj 25
integration
October 28 2023
1  9

Hi

Why, when I run the integral command, it only prints the integral instead of solving it?

display the '*' symbol when using "Parse"...

Asked by: jalal 445
inertform
October 28 2023
0  3

Hi, I'm looking to create a series of random exercises on square roots for my students with two objectives: Simplify square roots and rationalize the denominator. Here's my scenario: I'm using the properties of the table to display the question and its solution, and generate a PDF with a good layout. I have two issues with the code: I don't want to display the '*' symbol when using "Parse" for "ex1" and "ex2," and I want only one denominator to be displayed for "Sol2." Thank you very much for your insights

AléatoireSérieRadicauxTEST.mw

TestRacineCarrée.pdf

Slow manipulations in Maple Standard GUI...

Asked by: Andriy 270
performance worksheet gui
October 27 2023
1  3

Hi all

I need your advice on Maple usage after a long break. I installed Maple on my laptop and first of all tried to launch my old program. Surprisingly, the old file opened. While the core Maple functionality remained familiar, the user interface had undergone some changes.

Yet, I soon encountered challenges when attempting to perform even the simplest operations, like file browsing or text selection; the Maple Standard GUI seemed uncharacteristically sluggish.  I switched to Maple Input mode but it didn't help much. Are there ways to improve my experience with Maple? Is it caused by the outdated hardware?

My system:
Ubuntu 22.04.3 LTS
Dell Inc. Latitude 5510 (1TB SSD, 32GB RAM).

Maybe it works much better on Windows?

Thank you for any suggestions.

how to compile Maple code for use without maple sy...

Asked by: 2cUniverse 115
codegeneration export compile
October 27 2023
1  4

How do I compile a larger maple code for usage without maple system ?

Thanks for support :)

How to separate reqired value from expression...

Asked by: AHSAN 160
polynomial solve rootfinding
October 27 2023
0  6

I am trying to separate a value by using solve common but could get the answer. Is there any way to get required expression

Simplification_Help.mw

error in calculating table values for time depend...

Asked by: KIRAN SAJJAN 40
homework pde numeric
October 27 2023
0  3
> 

restart
> 

with(PDEtools); with(plots)
> 

inf := 6
> 

Gr := 3; beta := 2; sigma1 := .2; alpha0 := .1; Pr := 7.1; E1 := .5; S := .7; Gm := 3; Kp := .2; Lat := .5; Lac := .5; Sc := .5; a1 := .5; Rd := 3
> 

OdeSys := {diff(Phid(eta, t), t)-Lac*(Phi(eta, t)-Phid(eta, t)) = 0, diff(Thetad(eta, t), t)-Lat*(Theta(eta, t)-Thetad(eta, t)) = 0, diff(Phi(eta, t), eta, eta)-Sc*(diff(Phi(eta, t), t))-Sc*a1*R*(Phi(eta, t)-Phid(eta, t)) = 0, diff(Theta(eta, t), eta, eta)-Pr*(diff(Theta(eta, t), t))-Rd*Theta(eta, t)-(2/3)*R*(Theta(eta, t)-Thetad(eta, t)) = 0, (1+1/beta)*(diff(U(eta, t), eta, eta))-(diff(U(eta, t), t))-Kp*U(eta, t)-R*(U(eta, t)-Ud(eta, t))+Gr*Theta(eta, t)+Gm*Phi(eta, t)+E1*exp(-S*eta) = 0, sigma1*(diff(Ud(eta, t), t))-U(eta, t)+Ud(eta, t) = 0}
> 

Cond := {Phi(0, t) = 1, Phi(eta, 0) = 0, Phi(inf, t) = 0, Phid(eta, 0) = 0, Theta(eta, 0) = 0, Theta(inf, t) = 0, Thetad(eta, 0) = 0, U(0, t) = t, U(eta, 0) = 0, U(inf, t) = 0, Ud(eta, 0) = 0, (D[1](Theta))(0, t) = -alpha0*(-1+Theta(0, t))}
> 

OdeSys1 := {diff(Phid1(eta, t), t)-Lac*(Phi1(eta, t)-Phid1(eta, t)) = 0, diff(Thetad1(eta, t), t)-Lat*(Theta1(eta, t)-Thetad1(eta, t)) = 0, diff(Phi1(eta, t), eta, eta)-Sc*(diff(Phi1(eta, t), t))-Sc*a1*R*(Phi1(eta, t)-Phid1(eta, t)) = 0, diff(Theta1(eta, t), eta, eta)-Pr*(diff(Theta1(eta, t), t))-Rd*Theta1(eta, t)-(2/3)*R*(Theta1(eta, t)-Thetad1(eta, t)) = 0, (1+1/beta)*(diff(U1(eta, t), eta, eta))-(diff(U1(eta, t), t))-Kp*U1(eta, t)-R*(U1(eta, t)-Ud1(eta, t))+Gr*Theta1(eta, t)+Gm*Phi1(eta, t)+E1*exp(-S*eta) = 0, sigma1*(diff(Ud1(eta, t), t))-U1(eta, t)+Ud1(eta, t) = 0}
> 

Cond1 := {Phi1(0, t) = 1, Phi1(eta, 0) = 0, Phi1(inf, t) = 0, Phid1(eta, 0) = 0, Theta1(eta, 0) = 0, Theta1(inf, t) = 0, Thetad1(eta, 0) = 0, U1(0, t) = 1, U1(eta, 0) = 0, U1(inf, t) = 0, Ud1(eta, 0) = 0, (D[1](Theta1))(0, t) = -alpha0*(-1+Theta1(0, t))}
> 

``
> 

NULL
> 

NULL
> 

colour := [red, green, blue, black]
> 

RVals := [1, 5, 10, 20]
> 

NULL
> 

for j to numelems(RVals) do Ans := pdsolve((eval([OdeSys, Cond], R = RVals[j]))[], numeric, time = t, spacestep = 0.25e-1, timestep = 1); Ans1 := pdsolve((eval([OdeSys1, Cond1], R = RVals[j]))[], numeric, time = t, spacestep = 0.25e-1, timestep = 1) end do
> 

interface(rtablesize = 100); interface(displayprecision = 5); Matrix([[eta, `&Nu;u1`, `&Nu;ud1`, Shr1, Shrd1, `&Nu;u2`, `&Nu;ud2`, Shr2, Shrd2, `&Nu;u3`, `&Nu;ud3`, Shr3, Shrd3, `&Nu;u4`, `&Nu;ud4`, Shr4, Shrd4], seq([seq([(eval(diff(Theta(.5, eta), eta), Ans[k]))(0), (eval(diff(Phi(.5, eta), eta), Ans[k]))(0), (eval(Thetad(.5, eta), Ans[k]))(0), (eval(Phid(.5, eta), Ans[k]))(0)][], k = 1 .. numelems(RVals))])]); interface(rtablesize = 10); interface(displayprecision = -1)

Error, index must evaluate to a name when indexing a module

  
> 

interface(rtablesize = 100); interface(displayprecision = 5); Matrix([[eta, `&Nu;u1`, `&Nu;ud1`, Shr1, Shrd1, `&Nu;u2`, `&Nu;ud2`, Shr2, Shrd2, `&Nu;u3`, `&Nu;ud3`, Shr3, Shrd3, `&Nu;u4`, `&Nu;ud4`, Shr4, Shrd4], seq([seq([(eval(diff(Theta1(1.1, eta), eta), Ans1[k]))(0), (eval(diff(Phi1(1.1, eta), eta), Ans1[k]))(0), (eval(Thetad1(1.1, eta), Ans1[k]))(0), (eval(Phid1(1.1, eta), Ans1[k]))(0)][], k = 1 .. numelems(RVals))])]); interface(rtablesize = 10); interface(displayprecision = -1)

Error, index must evaluate to a name when indexing a module

  
> 

NULL

Download error_in_table_value.mw

labels and tickmarks problem...

Asked by: jestrup 70
plotting tickmarks
October 26 2023
1  6

I have a small problem that I can't find a solution for. How do you draw a diagram like the one shown in Maple? I can't figure out how to rotate the column labels or define tickmarks as text.

Can anyone help?

Modal Analysis: How to pause and zoom into the an...

Asked by: C_R 3442
animation modal
October 26 2023
0  0

Modal Analysis is a very usefull feature. Only the animation window is sometimes too tiny.

How to enlarge this view and to pause the animation?

This seems to be a Maple plot window (a "Rotate the view" cursor is visible and the animation can be rotated). Are there any short cuts or functions keys to toggle plot view options?

Edit: Looks to my like a Maplet. Maybe a Maplet programmer can tell if that (what I am asking) is possible

Problem viewing data tables in maple cloud viewer...

Asked by: Jean-Baptiste Runge 5
maplecloud datatable
October 26 2023
1  1

Hi, 

Some of my maple documents contain data tables. 

When I want to view these documents with the maple cloud viewer, the data tables are invisible (the table is completely grayed out) and it is therefore impossible to change the values in this table. 

The table properties are such that it is enabled, visible and editable. 
Does anyone have an idea how to solve this problem? 
Thanks in advance. 

Converting a Maple program to JavaScript ...

Asked by: 2cUniverse 115
codegeneration javascript
October 26 2023
1  0

Whats the best way to let a Maple-Code run in webspace.

The Maple-Procedure gets some parameters from a mobile-App. Then doing calculations and giving back data as a file to the mobile app.

I have alomost decided for Deno which accepts Javascript. This is develeoped by Ryan Dahl who has also created Node.

Deno is more compact and very fast. So I when I use a deno server code  then I need the Maple-Code in language Javascript.

I have tried to translate some maple-subprocedures of my code with CodeGeneration but this is very restricted I think.

Thanks for ideas :)

How to generate a random operation from [+,x,-]?...

Asked by: jalal 445
October 26 2023
0  5

Hi,

How to generate a random operation from [+,x,-]?

Thanks

How to count number of occurrences ...

Asked by: Maxwell_ludwig 5
polynomial degree
October 25 2023
1  3

Let us say that I have an expression, x*y*z^2*w^3 for example and I want to know the number of occurrances of x,y,z and w. 

So far I have tried splitting into a list and using nops, but I run into the problem that the z^2 and any power term seems to only be counted as one element (which makes sense).

I have also tried using the numboccur command but I have the same issue. I guess my question is, how can I convert this expression into "x*y*z*z*w*w*w" so that I can count w^3 as 3 occurances rather than 1? 

Thank you in advance for any suggestions!

How do I fix error in Array?...

Asked by: Carolyn Davis 15
syntax sin user-error
October 24 2023
0  1

Can anyone please assist with these errors?

> 

#Clear memory.
restart;

#Initialise variables and arrays.
h:=Pi/10;
n:=10;
k:=0.1;  
m:=6;
t:=Array(0..m):
x:=Array(0..n):
u:=Array(0..n,0..m):

#Initialise the x array and the initial u(x,0) boundary.
for i from 0 to n do
    x[i]:=i*h;
    u[i,0]:=0;
end do:

#Initialise the t array and the u(x,t) side boundaries.
for j from 0 to m do
   t[j]:=j*k;
   u[0,j]:=0;
   u[n,j]:=3*sin*t[j];
end do:

#Use the 2D CTCS explicit wave method.
for i from 1 to n-1 do
   u[i,1]:=(u[i-1,0]/2*Pi^2+sin(x)/10*Pi^2+u[i+1,0]/2*Pi^2)-1;
end do:
 
for j from 1 to m-1 do
  for i from 1 to n-1 do
   u[i,j+1]:=(((u[i-1,j]+u[i+1,j]-u[i,j-1])/Pi^2)-2);
  end do;
end do:

#Display the u(x,t)values.
printf("2D CTCS Explicit Wave Method\n");
printf("----------------------------\n");
printf("x\t\t t\t\t u\n");
for i from 0 to n do
   printf("% f\t% f\t% f\n",x[i],t[m],u[i,m]);
end do;

(1/10)*Pi

  

10

  

.1

  

6

  

Error, invalid input: sin expects its 1st argument, x, to be of type algebraic, but received Array(0..10, [0,1/10*Pi,1/5*Pi,3/10*Pi,2/5*Pi,1/2*Pi,3/5*Pi,7/10*Pi,4/5*Pi,9/10*Pi,Pi])

  

2D CTCS Explicit Wave Method
----------------------------
x                 t                 u
 0.000000         0.600000         0.000000
 0.314159         0.600000        -2.015556
 0.628319         0.600000        -2.198509
 0.942478         0.600000        -2.215724
 1.256637         0.600000        -2.218015
 1.570796         0.600000        

  

Error, (in fprintf) number expected for floating point format

  
> 

NULL


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