@vv 

I'd just figured oout how to do this (more or less the saem way)

See the attached

Download Koch2.mw

@HamidAhmadi 

BC4 := 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Is this intended as a meaningful contribution? Because it is meaningless

@HamidAhmadi 

The user does

using the big green up-arrow in the Mapleprimes toolbar

in the Mapleprimes toolbar to upload the worksheet which demonstrates the problem

From the error message you post - I'm suspicious about the existence of the sqare and curly bracket characters (ie '{' and ']' ) in the error message. The delimiters {} denote a set, and the delimiters [] denote a list

for the coefficients, simply because the term a-b may be positive or negative depending on the numerical values of 'a' and 'b'. So for your case, the coefficient of depends on the numerical values of the parameters

I[f], I[r], Lambda[r], N[H], N[f], S[H], S[r], b[Hf], b[fH], b[fr], b[rf], beta[fH], beta[fr], beta[H*f], beta[r*f], lambda[H], mu[B], mu[H], mu[f], mu[rd], tau[H]

Since the values of none  of these parameters are known, the sign of any coefficient is obviously unknown

Consider an expression a-b where all parameters are positive

Is it positive or negative?

It depends!

If a>b, it is positive: if a<b it is negative

consider the expression a*². Is the sign of the coefficient of ² positve or negative? Well.... it depends on the value of the parameter 'a'.

In your worksheet you have some reasonably complicated expressions for the coefficients of the polynomial in  Whether these coefficients are positive or negative is entirely dependent on the numerical values of the parameters on which the coefficient depends.

Consider the term (a-b)*². The coefficient is positive if a>b and negative if a<b.

So exactly what do you mean when you say you want to know the sign of coefficient?

When posting questions here it is usually very helpful if you include a relevant worksheet. (Use the big green up-arrow in the Mapleprimes toolbar to upload worksheets)

Clarify

1. which are the equations you wish to solve?
2. which are the variables you wiish to solve for?
3. which are parameters? In your post 'a' and 'b' seem to be parameters, but it doesn't make much sense to impose inequality conditions on parameters(?)
4. is a numerical solution feasible/possible?

@Carl Love 

for the simple reason, that this undesirable behaviour only occurs (as far as I can tell?!) when a variable name contains an inert suffix.

The problem appears to only affect variable name display. But this just begs the question: exactly why should variables whose names have inert suffixes be displayed 'incorrectly'??

A second (possibly related?) issue. Why is the assumption indicator (the trailing tilda) typeset at the suffix level? I mean displaying the variable U_LL~ as U_LL~U_LL~ is already wrong. Displaying it as U_LL~U_LL~ is (somehow) even more wrong!

See the attached - noting carefully that when workseets are displayed inline on this site, the display problem "disappears", so the following (display) does not illustrate the problem: you have to download/execute the worksheet

Download assum.mw

attached anywhere?????

Use the big green up-arrow in the MaplePrimes toolbar to attach worksheets

@marwan12345 

1. If you read the help page for 'spacecurve' this will inform you how to plot your "moment curve"
2. If you read the help page for 'Student[VectorCalculus]:-TangentLine', this wiill inform you how to generate the tangent to any curve, including the one defined at (1) above
3. If you have read the help page at (1) above, then you will know how to plot the line obtained at (2) above
4. If you read the help page for 'plots:-display', this will inform you how to combine the plots obtained in (2) and (3) above in the same figure

@Kitonum 

It would seem that many of the DrawGraph() options are ignored if the dimension=3 option is used.

In particular the capability to color edges and vertexes using "stylesheet". See the attached

I find this behaviour rather "disappointing"

Download grplt.mw

This is a user forum for Maple not Matlab

I suggest you post this problem on a Matlab user form!

The code snippet you have supplied contains the unassigned variables De, b, c, h

Hence no-one can obtain the solution/graph which you supply, or indeed do any meaningful calculations

I recommend you post an actual worksheet using the big green up-arrow in the Mapleprimes toolbar