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MaplePrimes Questions

matrix equation ...

Asked by: yangtheary 215
linear-algebra characteristic_polynomial
May 23 2023
0  1

how to show the subject's path?...

Asked by: ArthurD 5
ode animation homework
May 23 2023
1  3

Hello,

I want to animate a ball rolling on the surface cos(abs(x)+abs(y)).  The ball mass m is 1kg, radius r is 0.1meters starts at (0.5,0.5,cos(abs(5)+abs(5))) meters using g=9.8. 

If we say the initial velocity of the ball is pushed in some random direction. 

How do I show the path of the ball and animate?

Thanks,

Arthur

how to do loop with 2 formula...

Asked by: syahirah rahimi 15
do-loop duplicate-question
May 23 2023
1  2


there’s few redundant values. I just want the positive values. How it can be done?

> 

restart
> 

NULL
> 

n := [80, 79, 83, 84, 83, 83, 81, 85, 86, 86, 83, 82, 83, 84, 81, 80, 83, 79, 82, 81, 85]

[80, 79, 83, 84, 83, 83, 81, 85, 86, 86, 83, 82, 83, 84, 81, 80, 83, 79, 82, 81, 85]

 (1)
> 

``
> 

nops(n)

21

 (2)
> 

for i from 3 to 17 do f[i] := n[i-2]-3*n[i-1]+3*n[i]; i = i+1; f[i+1] := n[i-2]+4*n[i-1]-6*n[i]+n[i+1] end do

92

  

3 = 4

  

-18

  

82

  

4 = 5

  

-10

  

80

  

5 = 6

  

4

  

84

  

6 = 7

  

-1

  

77

  

7 = 8

  

14

  

95

  

8 = 9

  

-17

  

84

  

9 = 10

  

-9

  

85

  

10 = 11

  

-4

  

77

  

11 = 12

  

14

  

83

  

12 = 13

  

9

  

86

  

13 = 14

  

-3

  

85

  

14 = 15

  

-9

  

74

  

15 = 16

  

13

  

81

  

16 = 17

  

11

  

90

  

17 = 18

  

-18

 (3)
> 

``
> 

NULL


 

Download fyp_2.mw

How to create Random question with Grading Package...

Asked by: jalal 270
grading
May 22 2023
0  9

Hi,

I am exploring the Grading package in Maple, and I want to create a random question about limits. (Question 9). Any ideas for the correct code? Thank you

QUIZZTestMaple.mw

seq slower than proc ...

Asked by: Harry Garst 224
performance programming linear-algebra
May 22 2023
1  5

I learned about Dodgson calculation of the determinant only recently (https://en.m.wikipedia.org/wiki/Dodgson_condensation).
I am only interested in symbolic expressions of the determinant.
Furthermore, I compared several methods. Not surprisingly, the build in method is the fastest. But why is the seq method slower than the proc method for the Dodgson method? Is there anything I could do to program it more efficiently?
 

> 

restart; with(LinearAlgebra)
> 

with(combinat); with(GroupTheory)
> 

DetDef := proc (A) local i, n, sigma; description "Jeremy Johnson. Downloaded from https://www.cs.drexel.edu/~jjohnson/2016-17/winter/cs300/lectures/determinant.mw"; n := RowDimension(A); add(PermParity(Perm(sigma))*mul(A[i, sigma[i]], i = 1 .. n), `in`(sigma, permute([`$`(1 .. n)]))) end proc
> 

InnerMatrix := proc (M::Matrix) SubMatrix(M, 2 .. RowDimension(M)-1, 2 .. ColumnDimension(M)-1) end proc
> 

MatrixDet := proc (M::Matrix) local C, n, i, j; n := RowDimension(M)-1; C := Matrix(n, n); seq(seq(assign('C[i, j]', Determinant(M([i, i+1], [j, j+1]))), j = 1 .. n), i = 1 .. n); return C end proc
> 

Dodgson := proc(M::Matrix)
 MatrixDet(M);
InnerMatrix(M) ^~ (-1) *~ MatrixDet(MatrixDet(M));
do if 1 < RowDimension(%) then InnerMatrix(`%%`) ^~ (-1) *~ MatrixDet(%);
end if;
until RowDimension(%) = 1;
Trace(%):
end proc:
> 

Dodgsonseq := proc (E::Matrix) local w, dim, Z; dim := RowDimension(E); Z[dim] := E; Z[dim-1] := MatrixDet(E); Z[dim-2] := `~`[`*`](`~`[`^`](InnerMatrix(E), -1), MatrixDet(MatrixDet(E))); seq(assign('Z[w-1]', `~`[`*`](`~`[`^`](InnerMatrix(Z[w+1]), -1), MatrixDet(Z[w]))), w = dim-1 .. 1, -1); Trace(Z[1]) end proc
> 

LaPlace := proc (M::Matrix) local c; add((-1)^(c+1)*M[1, c]*Minor(M, 1, c), c = 1 .. ColumnDimension(M)) end proc
> 

dim := 7; A := Matrix(dim, dim, shape = symmetric, symbol = a)

7

 (1)
> 

start_time := time(); st := time[real](); Det1 := abs(A); CPUtime_used_Build_in_Determinant := time()-start_time; REALtime_used_Build_in_Determinant := time[real]()-st; start_time := time(); st := time[real](); Det2 := DetDef(A); CPUtime_used_Jeremy_Johnson_Determinant := time()-start_time; REALtime_used_Jeremy_Johnson_Determinant := time[real]()-st; start_time := time(); st := time[real](); Det3 := Dodgsonseq(A); CPUtime_usedDodgsonseq := time()-start_time; REALCPUtime_usedDodgsonseq := time[real]()-st; start_time := time(); st := time[real](); Det4 := Dodgson(A); CPUtime_usedDodgson := time()-start_time; REALtime_usedDodgson := time[real]()-st; start_time := time(); st := time[real](); Det5 := LaPlace(A); CPUtime_usedLaPlace := time()-start_time; REALtime_usedLaPlace := time[real]()-st; simplify(Det1-Det2); simplify(Det1-Det3); simplify(Det1-Det4); simplify(Det1-Det5)
``

0.32e-1

  

0.34e-1

  

0.93e-1

  

.108