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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Fourth way by programming,

J code:

```
a=:i.1000
+/+/(+/"1(3#10)#:a)=/+/"1(3#10)#:a
```

We can shorten that a little:

`+/+/=/~+/"1(3#10)#:a`

*Last edited by gAr (2013-09-25 19:30:02)*

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense" - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

New problem:

**A fair coin is tossed 20 times. What is the probability that there will be 5 or more consecutive heads?**

*Last edited by gAr (2013-11-24 02:45:44)*

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense" - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Hi gAr;

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi bobbym,

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense" - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Hi gAr;

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Hi gAr;

Trying to convince Agnishom to do some computer math.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

That's nice, I think he's already doing some.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Yes, some of my bad influence rubs off on most people sooner or later.

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

You're not a bad influence.

I ask people to stay away from non-free softwares, but most of them are reluctant to learn!

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Have you been keeping up with geogebra? They are almost done with it. Do you like the 3D?

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Haven't used the recent releases.

Last time when I used 3D, processor was running at 100% even when left idle, don't know now.

Any significant changes you observed?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

I am not a big fan of 3D programs to begin with. I prefer living like a flatlander. I think they have come along alot but still need more work.

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Me neither.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

I thought it was a little slow on my machine but it is only a dual core.

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Even mine is a dual core, but I think it doesn't matter for most of the applications.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Also, my graphics card is the low end one.

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

That's fine, CAS wouldn't require a graphics card. Though I think I've read recent mathematica versions make use of it.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Yes, they use the Nvidia Cuda card. It speeds up things tremendously, I have a Radeon card.

Graphics are important when plotting 3D especially.

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Yes, that's right.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Not that I do alot of 3D work. I do not think there is any CAS that is as good as some other programs are at graphing.

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

I too rarely use 3d, and I recently saw that there's an option to view the plot in stereographic view in sage. But didn't try with the glasses yet.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

What kind of glasses do you use for it?

**In mathematics, you don't understand things. You just get used to them.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

The red and cyan glasses, like the ones used for viewing 3d films.

By the way, is it feasible to create an option to mark the posts containing problems, and then create the links to those posts in one place (e.g. in the beginning of the thread)?

That will make the problems more visible.

*Last edited by gAr (2013-11-20 17:26:04)*

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 91,413

Hi;

I am not able to do that. It would have to be done with source code of the forum.

**In mathematics, you don't understand things. You just get used to them.**

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