## 240 Reputation

7 years, 242 days

## @acer Actually the amount of t is very s...

@acer Actually the amount of t is very small, I corrected it, but could not get the answer.

 >
 >
 >
 >
 >
 >
 >
 (1)

## {seq(V[1, r] = q, r = 1 .. 4)} does not ...

@acer I used {seq(V[r] = q .. X[r], r = 1 .. 4)} because I want to solve the equation within that interval only. {seq(V[1, r] = q, r = 1 .. 4)} does not define interval.
Any help to considering intervals within fsolve?

## imaginary part!!??...

@vv results also imaginary part. why???

## You mean there is not a way to find such...

@Carl Love I did it manually as below (rational elements of matrix A):

 >
 >
 >
 >
 >
 >
 >
 (1)
 >
 (2)
 >
 (3)
 >
 (4)
 >
 >
 >
 >
 (5)
 >
 >

You mean there is not generally a way to find such coefficient matrices!???

## @Carl Love Your method could not solve m...

@Carl Love Your method could not solve my problem yet. Let me explain my problem simply.

I want to earn the coefficient matrix (A) of the following equations:

f1 := (a+2*b+c+5*d)^3;
f2 := (3*a+b+4*c+d)^3;
f3 := (a+b+5*c+d)^3;
f4 := (a+2*b+c+6*d)^3;

The above equations can be written in the following form:

f=A(a,b,c,d)X

Which X= Transpose{a b c d}

and A is a matrix which its element are functions of a,b,c,d.

I am looking for rational A

## Error, (in Matrix) unable to compute coe...

@Carl Love When me equation has time derivatives of the variables, your method face an eeror!Download GenMatrix.mw

Error, (in Matrix) unable to compute coeff

 >
 >
 >
 >
 >
 >
 >
 >
 >

## @Carl Love Thanks, Nice method you used,...

@Carl Love Thanks, Nice method you used, but why the GererateMatrix can not do so???

## @Rouben Rostamian  Thanks Rouben,&n...

@Rouben Rostamian  Thanks Rouben,  Yes since in the provided example y can be solved in terms of x, the integration can be done easily. But in my early problem y can not be solved in terms of x, so it seems the area (integral) of the projected intersection curve can not be calculated easily.

I am looking for the equation of projected curve or at least find a way to calculate the projected area (S) and center of area (C.A), as below:

## @vv Actually I want to find the equation...

@vv Actually I want to find the equation of the projected curve. How is it possible in Maple?

If it is not possible, what a bout curve fitting? (extract enough numbers of points then fit a curve for it). I am looking for easiest and fast way.

## Also takes time for postprocessing cacul...

@mmcdara I also tryed usng this m files, although the file is read successfully, the postprocessing which occurs after intialization takes so time to be done.

Any other way???/

## takes long time...

@tomleslie as i said the matrix sise is big, so importing it to the new worksheet takes long time.

restart;
currentdir("E:/Project/");

ImportMatrix(f);

I attached f here, please delete .txt extension

```
```

## @Rouben Rostamian  I provided the e...

@Rouben Rostamian  I provided the example, you can look at it.

## Shirt information...

@dharr I attached a short information about this method which may help others to understand and use this method in such problems.

ShortInfo.pdf

## @dharr Unfortunately, in this method Q2 ...

@dharr Unfortunately, in this method Q2 is rectangular (2000*1200) not square.

 1 2 3 4 5 6 7 Page 2 of 9
﻿