## Alec Mihailovs

Dr. Aleksandrs Mihailovs

## 4470 Reputation

20 years, 25 days
Mihailovs, Inc.
Owner, President, and CEO
Tyngsboro, Massachusetts, United States

## Social Networks and Content at Maplesoft.com

I received my Ph.D. from the University of Pennsylvania in 1998 and I have been teaching since then at SUNY Oneonta for 1 year, at Shepherd University for 5 years, at Tennessee Tech for 2 years, at Lane College for 1 year, and this year I taught at the University of Massachusetts Lowell. My research interests include Representation Theory and Combinatorics.

## MaplePrimes Activity

### These are replies submitted by Alec Mihailovs

I've just voted up all you posted thus far, so hopefully you are getting there (where you'll be able to vote up :)

Alec

## Arrays...

I am on the go and can't check that immediately. I think, there were 4 Arrays in Q1. Maybe, all of them are the same?

Another possibility is that Q1 is a set and not a list, so maybe, one has to convert it to list first, before printing to a text file.

Alec

## Arrays...

I am on the go and can't check that immediately. I think, there were 4 Arrays in Q1. Maybe, all of them are the same?

Another possibility is that Q1 is a set and not a list, so maybe, one has to convert it to list first, before printing to a text file.

Alec

## normalized...

There is an option normalized.

The advantage of using it is that you don't have to add an artificial 3rd coordinate.

Alec

## normalized...

There is an option normalized.

The advantage of using it is that you don't have to add an artificial 3rd coordinate.

Alec

## PrincipalNormal...

VectorCalculus:-PrincipalNormal seems to be better suited for that.

Alec

## PrincipalNormal...

VectorCalculus:-PrincipalNormal seems to be better suited for that.

Alec

## Convert to a list or a seq...

For example,

```x:=<1,2,3>:
y:=convert(x,list)[];

y := 1, 2, 3

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

6
```

or

```z:=seq(i,i=x);

z := 1, 2, 3

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

6
```

It is not the "recommended" way, because add should be used here instead of sum, but might work for your purposes.

Alec

## Convert to a list or a seq...

For example,

```x:=<1,2,3>:
y:=convert(x,list)[];

y := 1, 2, 3

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

6
```

or

```z:=seq(i,i=x);

z := 1, 2, 3

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

6
```

It is not the "recommended" way, because add should be used here instead of sum, but might work for your purposes.

Alec

## asymptotes...

Instead of implicitplot, the following can be used for plotting,

```algcurves[plot_real_curve](16*x^4-y^4-y^3-3*x^2+y+1, x, y,
view=[-2..2, -4..4], scaling=constrained);
```

One of asymptotes in this example could be found as

```x=convert(asympt(RootOf(16*x^4-y^4-y^3-3*x^2+y+1,x),y,1),polynom);

x = - y/2 - 1/8

solve({%},y)[];

y = -2 x - 1/4
```

and another one follows from the symmetry,

```eval(%,x=-x);

y = 2 x - 1/4
```

Trying doing that as in the first example in this thread shows a bug in asympt,

```restart;
asympt(RootOf(16*x^4-y^4-y^3-3*x^2+y+1,y),x,2);

pt
```

(which sounds as pity).

Alec

## asymptotes...

Instead of implicitplot, the following can be used for plotting,

```algcurves[plot_real_curve](16*x^4-y^4-y^3-3*x^2+y+1, x, y,
view=[-2..2, -4..4], scaling=constrained);
```

One of asymptotes in this example could be found as

```x=convert(asympt(RootOf(16*x^4-y^4-y^3-3*x^2+y+1,x),y,1),polynom);

x = - y/2 - 1/8

solve({%},y)[];

y = -2 x - 1/4
```

and another one follows from the symmetry,

```eval(%,x=-x);

y = 2 x - 1/4
```

Trying doing that as in the first example in this thread shows a bug in asympt,

```restart;
asympt(RootOf(16*x^4-y^4-y^3-3*x^2+y+1,y),x,2);

pt
```

(which sounds as pity).

Alec

## Yes...

Yes, it's from a thread on how to select real roots from the solve output, I think. But there might be a couple of other quotes as well. Perhaps, he didn't exactly use the word "plague", but the meaning was similar.

It's nice that you have those archives saved. I used to have some, but not everything, and then after a couple of hard drive crashes, I lost a lot, and not everything was backed-up.

Alec

## Yes...

Yes, it's from a thread on how to select real roots from the solve output, I think. But there might be a couple of other quotes as well. Perhaps, he didn't exactly use the word "plague", but the meaning was similar.

It's nice that you have those archives saved. I used to have some, but not everything, and then after a couple of hard drive crashes, I lost a lot, and not everything was backed-up.

Alec

## Welcome...

Welcome to the community!

Alec