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#1 2011-06-21 06:42:22

soroban
Member
Registered: 2007-03-09
Posts: 452

Rubbish?

tan(A+B) =  sin^2A - sin^2B/sinA cosA - sinB cosB





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. .



. .


.

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#2 2011-06-21 07:38:26

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,657

Re: Rubbish?

hi soroban
you tell him.
the person who posted "what rubbish is this??" 'clearly' doesn't know the rules for trigonometric functions of sums.


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#3 2011-06-21 10:10:06

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,552

Re: Rubbish?

They seem to think we can read their mind.


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#4 2011-06-21 10:53:14

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,543

Re: Rubbish?

Hi;

Soon to be released in JAMA.

Definition: Bracketophobia - an unusual or unwarranted fear of brackets or parentheses.

Treatment: Latexicillin or OxyLatex. Massive doses required.

Contraindications: Some patients have been known to become aggressive when the slightest suggestion of bracketing is made. Stronger treatment may be required.


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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#5 2011-06-24 05:40:14

soroban
Member
Registered: 2007-03-09
Posts: 452

Re: Rubbish?

. .

.

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#6 2011-06-24 05:45:06

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,543

Re: Rubbish?

Hi soroban;

Have you seen the movie "A Beautiful Mind?" He would fill up a blackboard, writing at all angles so that all the space would be used. He would even write inside of a zero.


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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#7 2011-06-24 06:09:51

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

Re: Rubbish?

I hate watching movies involving science/mathematics/computers.
Rarely are they anywhere near reality.

Someone looks at a code, his mind magically deciphers it!
Someone presses keyboard keys randomly, and he breaks into a system!
Some IP addresses go above 255 in quad dotted notation!

Even the media are no better.
Better stay uninformed than disinformed!!


"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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#8 2011-06-24 06:18:56

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,543

Re: Rubbish?

True! The Numbers show on tv is among the worst.

In the movies computers are so smart. They always take over the world.

But I am getting carried away, sticking to the topic.

I can decipher it but not condone it. When I was young I used to write math pretty much like that. Used to make my teachers very angry.


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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#9 2011-06-24 06:26:52

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

Re: Rubbish?

I think it's not out of topic, it's "rubbish"!

Anyway,regarding that serial assignment, it would be fun if it's shown to a programmer!


"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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#10 2011-06-27 12:41:06

soroban
Member
Registered: 2007-03-09
Posts: 452

Re: Rubbish?

gAr wrote:

I hate watching movies involving science/mathematics/computers.
Rarely are they anywhere near reality.

I agree . . .

What about this?

Two men are playing a chess game.
The villain makes a move and sits back, smiling smugly.
The hero (usually James Bond) looks a bit concerned,
. . then makes a move . . . Checkmate!
The villain's jaw drops . . . totally stunned!

You'll never convince me that someone who plays chess
. . would overlook a mate-in-one ... and walk into it.

.

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#11 2011-06-27 14:59:05

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,543

Re: Rubbish?

Hi;

Although those type of errors are much more prevalent in weaker players they occasionally pop up even in grandmaster games.

I believe both Tigran Petrosian and Emanuel Lasker, both world champions walked into simple mates in the middle of the board. Petrosian lost his queen in a very important tournament to determine the next challenger. Bobby Fischer was guilty of a touch move as was Garry Kasparov ( also world champions ).

My worst one was walking into a simple 2 move mate on the back rank.


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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