MaplePrimes Questions

Writing an explanatory paragrah i want to use an approximately equal symbol. How can I do this? The palette has lots of symbols but not what in latex would be done with \approx

I just tried to solve a very simple system of equations using solve but depending on how I write the system the command does out give any output. 

restart

solve({I__cm = m*r^2, r*T = I__cm*a/r, g*m-T = m*a}, {T, a})

solve({r*T = m*r^2*a*(1/r), g*m-T = m*a}, {T, a})

{T = (1/2)*m*g, a = (1/2)*g}

(1)

NULL

Solution with pencil and paper

T := (1/2)*m*g = (1/2)*m*gNULL

a := (1/2)*g = (1/2)*gNULL

Check this solution

evalb(g*m-T = m*a)

true

(2)

evalb(r*T = m*r^2*a*(1/r))

true

(3)

NULL


Notice that if I define I__cm then there is no solution being shown. I can rename I__cm to something else like y, still no output. Then in the second system I simply sub I__cm into the equation that has this variable, and it works.

So what's going on here? Why doesn't the first use of solve work?

Download solveSys.mw

How to read the topological structure of chemical from a SMILES file in Maple 

As I want only the physical structure of the molecule

Like in molecular data it gives the bonds of topology {1,2} like the structure it gives

As SMILES can give 2D structure to me 

Kind help how to do 

My following code:

restart;
PDE := diff(u(x, t), t) + u(x, t)*diff(u(x, t), x) - 0.1*diff(diff(u(x, t), x), x) = 0;
IC := u(x, 0) = sin(x);
BC := [u(0, t) = u(2*Pi, t)];
pds := {BC, IC, PDE};
ds := {pds, t = 0 .. 10, x = 0 .. 2*Pi};
p := pdsolve(ds, numeric);
u := rhs(p[1]);
u(x, t);

producing following 2 errors, don't know how to handle?

Error, (in anonymous procedure called from pdsolve/numeric) invalid terms in sum: 0 .. 10
Error, invalid input: rhs received p[1], which is not valid for its 1st argument, expr

How to make this program more effective ?
 

A := [-3, 1, 2];
B := [-2, -1, 1];
C := [0, 3, -3];
                        A := [-3, 1, 2]

                        B := [-2, -1, 1]

                        C := [0, 3, -3]

alpha[1] := 2;#weight
alpha[2] := -1;
alpha[3] := 1;
                         alpha[1] := 2

                         alpha[2] := -1

                         alpha[3] := 1

x[1] := A[1];
x[2] := B[1];
x[3] := C[1];
                           x[1] := -3

                           x[2] := -2

                           x[3] := 0

y[1] := A[2];
y[2] := B[2];
y[3] := C[2];
                           y[1] := 1

                           y[2] := -1

                           y[3] := 3

z[1] := A[3];
z[2] := B[3];
z[3] := C[3];
                           z[1] := 2

                           z[2] := 1

                           z[3] := -3

sum(alpha[i], i = 1 .. 3);
                               2

xG := sum(alpha[i]*x[i], i = 1 .. 3)/sum(alpha[i], i = 1 .. 3);
                            xG := -2

yG := sum(alpha[i]*y[i], i = 1 .. 3)/sum(alpha[i], i = 1 .. 3);
                            yG := 3

zG := sum(alpha[i]*z[i], i = 1 .. 3)/sum(alpha[i], i = 1 .. 3);
                            zG := 0
Thank you.

Hello everybody! 

Since least squares is not fully understood by me all that well, and the way my Dutch book throws me into the deep whitout really showing how things are done, i decided to look for some videos on Least Squares in Maple on YouTube. Well, i did found one, but then this happened. "Error, (in sum) summation variable previously assigned, second argument evaluates to 1 = 1 .. 5" I just want to go further with the video, but now im stuck and i have no clue how to go on. 

https://youtu.be/8zh73UrJW6M?t=948 This is the video at the moment the part where i get stuck is shown. 

I really like these sort of videos while they really do help out. I think its great. 

This is my maple worksheet:


 

with(Statistics); with(CurveFitting); with(LinearAlgebra); with(Optimization); with(plots); interface(imaginaryunit = I)

I

(1)

"f(x):=b[0]+(∑)(b[k]*sin(k*x))"

proc (x) options operator, arrow, function_assign; b[0]+sum(b[k]*sin(k*x), k = 1 .. 5) end proc

(2)

X := [seq(3.*k*(1/10), k = 1 .. 10)]

[.3000000000, .6000000000, .9000000000, 1.200000000, 1.500000000, 1.800000000, 2.100000000, 2.400000000, 2.700000000, 3.000000000]

(3)

Y := map(proc (x) options operator, arrow; x^2 end proc, X)

[0.9000000000e-1, .3600000000, .8100000000, 1.440000000, 2.250000000, 3.240000000, 4.410000000, 5.760000000, 7.290000000, 9.000000000]

(4)

F := CurveFitting:-LeastSquares(X, Y, x, curve = f(x))

HFloat(9.017880939782968)-HFloat(7.700034497920161)*sin(x)-HFloat(3.0589327899122045)*sin(2.*x)-HFloat(1.6899646233017431)*sin(3.*x)-HFloat(1.40247653582845)*sin(4.*x)-HFloat(0.82531550630546)*sin(5.*x)

(5)

smartplot(HFloat(9.017880939782968)-HFloat(7.700034497920161)*sin(x)-HFloat(3.0589327899122045)*sin(2.*x)-HFloat(1.6899646233017431)*sin(3.*x)-HFloat(1.40247653582845)*sin(4.*x)-HFloat(0.82531550630546)*sin(5.*x))

 

display(data, plot(f(x), x = 0 .. 3))

Warning, expecting only range variable x in expression b[0]+b[1]*sin(x)+b[2]*sin(2*x)+b[3]*sin(3*x)+b[4]*sin(4*x)+b[5]*sin(5*x) to be plotted but found names [b[0], b[1], b[2], b[3], b[4], b[5]]

 

Error, (in plots:-display) expecting plot structure but received: data

 

data := LinearAlgebra:-Transpose(`<,>`(`<|>`(.3000000000, .6000000000, .9000000000, 1.200000000, 1.500000000, 1.800000000, 2.100000000, 2.400000000, 2.700000000, 3.000000000), `<|>`(0.9000000000e-1, .3600000000, .8100000000, 1.440000000, 2.250000000, 3.240000000, 4.410000000, 5.760000000, 7.290000000, 9.000000000)))

Matrix(%id = 18446746050376108382)

(6)

p1 := plot(data, style = point, color = "green")

 

display(p1, plot(F, x = 0 .. 3), plot(x^2, x = 0 .. 3, color = "black"))

 

with(CurveFitting)

``

CurveFitting[Interactive](X, Y)

9.01788093978297-7.70003449792016*sin(x)-3.0589327899122*sin(2.*x)-1.68996462330174*sin(3.*x)-1.40247653582845*sin(4.*x)-.82531550630546*sin(5.*x)

(7)

smartplot(9.01788093978297-7.70003449792016*sin(x)-3.0589327899122*sin(2.*x)-1.68996462330174*sin(3.*x)-1.40247653582845*sin(4.*x)-.82531550630546*sin(5.*x))

 

with*LinearAlgebra

LinearAlgebra:-LeastSquares({Equate(`~`[f](X), Y)[]}, {seq(b[k], k = 0 .. 5)})

{b[0] = HFloat(9.017880939782952), b[1] = HFloat(-7.700034497920145), b[2] = HFloat(-3.0589327899122054), b[3] = HFloat(-1.6899646233017416), b[4] = HFloat(-1.4024765358284492), b[5] = HFloat(-0.8253155063054547)}

(8)

A, v := LinearAlgebra:-GenerateMatrix(Equate(`~`[f](X), Y), [seq(b[k], k = 0 .. 5)]); LinearAlgebra:-LeastSquares(A, v)

Vector[column](%id = 18446746050376098150)

(9)

Optimization:-LSSolve([v, A])

[2.61443732196701051, Vector[column](%id = 18446746050376094654)]

(10)

Optimization:-LSSolve([seq(f(X[k])-Y[k], k = 1 .. 10)])

Error, (in sum) summation variable previously assigned, second argument evaluates to 1 = 1 .. 5

 

NULL


Thank you very much! 

Greetings,

 

The Function
 

Download Least-Squares_Fitting_in_Maple_video.mw

Is there a way to execute an entire worksheet for a list of values of a parameter.
Sometimes executing in the standard loop can be cumbersome given you have to add catch statements for errors to prevent the loop from stopping.

Hi,

I'm not able to find a way to bring an equation into it's "polynomial" form:

I'd like this expression in the form of:

c1*v^3+c2*v^2+c1*v+c0 = 0

where c1...c4 are my coefficients

How can I do that? 

Hello guys
I'm having trouble converting the RootOf function. Attached is a simple notebook.

Sincerely,

Oliveira

Example.mw

Dear Maple Users:

Could you help in the following question?

How do I use a symbol as a subscript, e.g.  A_*, to label an axis?

X := vector([seq(x, x = 1 .. 5)]);
Y := vector([seq(x, x = 6 .. 10)]);
X[1];
Y[1];
Yfactor := evalf(X[`1`])/Y[`1`];
evalf(Yfactor);
                      X := [1, 2, 3, 4, 5]

                     Y := [6, 7, 8, 9, 10]

                               1

                               6

                                         X[1]
                        Yfactor := -------
                                         Y[1]

                              X[1]
                              ----
                              Y[1]

m := 1;
X := vector([seq(x, x = 1 .. 5)]);
Y := vector([seq(x, x = 6 .. 10)]);
Yfactor := X[m]/Y[m];
evalf(Yfactor);
                             m := 1

                      X := [1, 2, 3, 4, 5]

                     Y := [6, 7, 8, 9, 10]

                                           1
                          Yfactor := ---
                                           6

                          0.1666666667

hi guys,

suppose we have general metric form in 4-D. I want to calculate Covariant derivative of Riemann, Ricci and Weyl tensors.

please help me.

with best,

I dont know why I could not solve this problem.

I have attached my worksheet.

Please anyone help me to get solution to this problem.

Thank you so much

fypppp.mw

DLMF offers different encodings for mathematical expressions. Example:

 

I was wondering if TeX or pMML (never seen before)  can be imported into Maple and subsequently be used as  Maple Input.

When taking notes I sometimes use the palette to insert a matrix into a worksheet. When I do this, the main aspect that is useful to me is being able to visualize matrix expressions as I would write them.

I would like to do the same but for determinants of matrices. Is there a way to get almost the same thing as with the matrix palette, but with vertical bars denoting a determinant rather than the brackets used for matrices?

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