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General => General Discussion => Topic started by: terravista on November 07, 2014, 09:32:56 AM

Title: Any maths guru's out there?
Post by: terravista on November 07, 2014, 09:32:56 AM
Hi
I received this image of a clock (if the upload works) and it is all equations using the number 9.
All seem pretty straight forward except the 7 o'clock requires rounding up the be dead accurate, but the 5 o'clock requires explanation.
What does the excalamation mark do to the equation to make this work?
Cheers
Ian
Title: Re: Any maths guru's out there?
Post by: paceman on November 07, 2014, 09:48:12 AM
not my explanation:

5 o'clock is the square root of nine (3), factorial (3x2x1 = 6), minus 9/9 (6-1 = 5).

7 o'clock, whose calculation works out to 6.99999..., with an infinite number of nines.


the exclamation point explained:

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. For example, 5 ! = 5 times 4 times 3 times 2 times 1 = 120
Title: Re: Any maths guru's out there?
Post by: terravista on November 07, 2014, 10:26:21 AM
Thanks paceman.
Great explanation.
Who would have thought I went through so many years and never heard of factorials.
More research on factorials show that they may also be called "shrieks" or "bangs". Maths sound like more fun than doing logarithms and trigonometry using books with a million printed numbers back in the 60's.
Cheers
Ian
Title: Re: Any maths guru's out there?
Post by: gronk on November 07, 2014, 11:31:54 AM
Sounds like some people don't go camping enough !!!!    ;D
Title: Re: Any maths guru's out there?
Post by: paceman on November 07, 2014, 11:44:23 AM
Sounds like some people don't go camping enough !!!!    ;D

knowing some of this is partly how i pay for my camping... :)
Title: Re: Any maths guru's out there?
Post by: NewieCamper on November 07, 2014, 12:04:42 PM
I remember back at school discovering that 69! into the calculator to ages to calculate and maxxed out the display. 70! gave an error. Or maybe it was 63!? Don't think I ever used that button for anything except not listening to the  teacher though.
Title: Re: Any maths guru's out there?
Post by: Barrabart on November 07, 2014, 12:05:36 PM
I'm no maths guru.

In fact I easily make two thick planks look like a computer................. when it comes to maths anyway....  :cheers:
Title: Re: Any maths guru's out there?
Post by: edz on November 07, 2014, 12:13:23 PM
Is that Big Bangs Sheldon's clock ... Why !!!
Title: Re: Any maths guru's out there?
Post by: muzza01 on November 07, 2014, 02:39:16 PM
The numeral nine 9 has special properties when it comes to maths.
Any number multiplied by 9 when disits are added together = 9

Eg 9 x 7 = 63.                         6 + 3 = 9

Eg 9 x 12 = 108                      1 + 0 + 8 = 9

Eg 9 x 149 = 1341                  1 + 3 + 4 + 1= 9

Eg 9 x 23456 = 211104.          2 + 1 + 1 + 1 + 0 + 4 = 9

Eg 9 x 987654 = 8888886       8 + 8 + 8 + 8 + 8 + 8 + 6 = 54.  5 + 4 = 9  ;D
Title: Re: Any maths guru's out there?
Post by: KingBilly on November 07, 2014, 02:58:14 PM
Plus you can do the nine times table simply by counting to nine.

9 x 1 = 9 that is the hardest one to do but you can use for fingers to help  ;D

Now count down the rest of the table:
9 x 2 = 1
9 x 3 = 2
9 x 4 = 3
9 x 5 = 4
9 x 6 = 5
9 x 7 = 6
9 x 8 = 7
9 x 9 = 8

No count them again from the bottom up:
9 x 2 = 18
9 x 3 = 27
9 x 4 = 36
9 x 5 = 45
9 x 6 = 54
9 x 7 = 63
9 x 8 = 72
9 x 9 = 81

KB
Title: Re: Any maths guru's out there?
Post by: gronk on November 07, 2014, 05:11:51 PM
knowing some of this is partly how i pay for my camping... :)

????  how so mate ??
Title: Re: Any maths guru's out there?
Post by: GeoffA on November 07, 2014, 05:30:46 PM
Secondary school maths.

Nice clock.... :cup:
Title: Re: Any maths guru's out there?
Post by: DannyG on November 07, 2014, 05:41:38 PM
All seems pretty straight forward

Ian, If all that seems pretty straight forward then you are clearly more of a maths guru that most of us ;D Nice clock though!
Title: Re: Any maths guru's out there?
Post by: koshari on November 07, 2014, 07:17:41 PM
I always wonder if we had 4 fingers on each hand if we would be octal people?

 
Title: Re: Any maths guru's out there?
Post by: speewa158 on November 07, 2014, 07:17:46 PM
Time is something that hangs on the wall , a fad out of Switzerland given time might catch on .
lf your tired Sleep
 lf your hungry eat
lf your thirsty drink  :cheers:
lf you have to go  , Go
                                               ;D :cheers: 
Title: Re: Any maths guru's out there?
Post by: brooke.fossey on November 07, 2014, 07:31:01 PM
Love the clock.  Where can I get one?
Title: Re: Any maths guru's out there?
Post by: Symon on November 07, 2014, 07:33:34 PM
Who would have thought I went through so many years and never heard of factorials.


I've only come across them when doing statistics.  I hate statistics, so I don't use them often :)

Where I really drew the line was with laplace transforms (http://en.wikipedia.org/wiki/Laplace_transform) hated that stuff with a passion.
Title: Re: Any maths guru's out there?
Post by: GeoffA on November 07, 2014, 09:13:08 PM
I've only come across them when doing statistics.  I hate statistics, so I don't use them often :)

Where I really drew the line was with laplace transforms (http://en.wikipedia.org/wiki/Laplace_transform) hated that stuff with a passion.


I didn't enjoy calculus at all....wasn't any more enjoyable when the kids did it, either.... :(
Title: Re: Any maths guru's out there?
Post by: Garfish on November 07, 2014, 09:36:00 PM
I loved matrices, and the imaginary number i, which allows the square root of negative numbers to be calculated....

Oh and permutation and combinations when the ! Becomes all too common
Title: Re: Any maths guru's out there?
Post by: gronk on November 07, 2014, 10:07:49 PM

Where I really drew the line was with laplace transforms (http://en.wikipedia.org/wiki/Laplace_transform) hated that stuff with a passion.


Ha, even though I had very little exposure, hexadecimal was another form of  calculation that I never got my head around fully ..
Title: Re: Any maths guru's out there?
Post by: prodigyrf on November 07, 2014, 11:20:09 PM
Long addition test for you and no cheating on Google. It's true in letter form (ignore the plus signs) so see if you can work out what numbers each letter represents to also make it true numerically.

FORTY
 +TEN
 +TEN
-------
SIXTY

And then when you've finished that simple task you need to tell me why my calculator can't work out the tangent of 90 degrees and who has been playing around with it and stuffed it up  >:(
Title: Re: Any maths guru's out there?
Post by: prodigyrf on November 07, 2014, 11:48:06 PM
And in case you've forgotten you don't get any marks for getting the right answer unless you can show how you got there  ;D
Title: Re: Any maths guru's out there?
Post by: nackdog on November 08, 2014, 12:20:19 AM
And then when you've finished that simple task you need to tell me why my calculator can't work out the tangent of 90 degrees and who has been playing around with it and stuffed it up  >:(
[/quote]

Is your calculator in degrees or radians? Should be in your options menu.
Title: Re: Any maths guru's out there?
Post by: speewa158 on November 08, 2014, 06:04:07 AM
lv just reread the posted ,,,,l think l need  :cheers:,,,,,,no l do need  :cheers:after all that  >:D
Title: Re: Any maths guru's out there?
Post by: Symon on November 08, 2014, 06:24:25 AM
I didn't enjoy calculus at all....wasn't any more enjoyable when the kids did it, either.... :(

Calculus is good if you have a good teacher, when I first learnt it in high school I really struggled, but in Yr 12 I got a better teacher and really got to like it.  The basic concept is rather simple, the way it is written (with all the different notations) is what makes it confusing.

I loved matrices, and the imaginary number i, which allows the square root of negative numbers to be calculated....

Oooo baby, now you are talking!  Kirchoff equations stuffed into a matrix, which spits out complex numbers like there is no tomorrow.  Love it.

Ha, even though I had very little exposure, hexadecimal was another form of  calculation that I never got my head around fully ..

It's just counting to 16 really, but since we don't have numerical symbols for 11-15 we use letters. i.e. 10=A, 11=B, 12=C, 13=D, 14=E, 15=F.  So "10" in hex is actually 16 in decimal.  It is easier to get your head around if you convert it all to binary first, and take 4 bit nibbles to convert to hex, and 3 bit nibbles to convert to oct, etc.

Is your calculator in degrees or radians? Should be in your options menu.

He's taking the piss.  Tan of 90 degrees is undefined.  Tan(90) = sin(90)/cos(90) = 1/0 and division by 0 is undefined.
Title: Re: Any maths guru's out there?
Post by: GeoffA on November 08, 2014, 06:36:56 AM
Calculus is good if you have a good teacher, when I first learnt it in high school I really struggled, but in Yr 12 I got a better teacher and really got to like it.  The basic concept is rather simple, the way it is written (with all the different notations) is what makes it confusing.

I envy that you got hold of it Symon. For me, it was the one that got away, but we have computers now.
Anything I might need calculus for, I can draw/model.....much easier, and far more enjoyable.
Title: Re: Any maths guru's out there?
Post by: fishfinder on November 08, 2014, 06:53:21 AM
wonder if there is a calendar with a simular format - it would take you three weeks to work out what day it is
Title: Re: Any maths guru's out there?
Post by: dales133 on November 08, 2014, 06:54:24 AM
Yep I hate math.
I know what I need for work but I'm numericly dyslexic.....If a whole bunch of numbers are thrown at me I just shut down lol.
Dosn't help my maths teacher in my formative years was a cock...thanks Mr Frederickson you tosser
Title: Re: Any maths guru's out there?
Post by: Mik01 on November 08, 2014, 07:29:54 AM
Here's another advanced formula for ya, I learnt as a kid in maths for dummies...

Punch these numbers into your calculator..
8008135

What does it spell?????  ;D
Title: Re: Any maths guru's out there?
Post by: Garfish on November 08, 2014, 08:26:52 AM
I always entered 5318008 and turned it upside down


Sent from my fingers via my brain
Title: Re: Any maths guru's out there?
Post by: prodigyrf on November 08, 2014, 08:57:50 AM
So do you dig trig or is it all Greek to you? Surprising the number of tradeys who never appreciate how useful it is now we have tan sine and cosine at the touch of a calculator button rather than looking it up in tables or with slide rules. Trig is imperative for building and setting out.
Title: Re: Any maths guru's out there?
Post by: Mik01 on November 08, 2014, 10:33:04 AM
I always entered 5318008 and turned it upside down


Sent from my fingers via my brain

Only the eggheads in advanced maths knew THAT formula.
Title: Re: Any maths guru's out there?
Post by: Garfish on November 08, 2014, 11:33:29 AM
Only the eggheads in advanced maths knew THAT formula.
With the old calculator 0.7734 used to work, because the 4 was displayed differently
Title: Re: Any maths guru's out there?
Post by: koshari on November 10, 2014, 10:06:32 AM
Ha, even though I had very little exposure, hexadecimal was another form of  calculation that I never got my head around fully ..
Hex is really just a neater way to represent large binary numbers.
Title: Re: Any maths guru's out there?
Post by: Footy Shorts Shane on November 18, 2014, 02:57:05 PM
You maths gurus might be able to help me ;D

With regards to psi and in hg, is one a linear form of the other, but in an opposite form of pressure? (That doesn't make much sense does it ??? )

Say if I had a mechanical force of 10 psi, applied to a valve, then added a 10 in hg vacuum to the same side of the valve, will this equal out zero?

Does that make sense?

Shane.
Title: Re: Any maths guru's out there?
Post by: Symon on November 18, 2014, 08:03:48 PM
You maths gurus might be able to help me ;D

With regards to psi and in hg, is one a linear form of the other, but in an opposite form of pressure? (That doesn't make much sense does it ??? )

Say if I had a mechanical force of 10 psi, applied to a valve, then added a 10 in hg vacuum to the same side of the valve, will this equal out zero?

Does that make sense?

Shane.

By hg, I assume you mean mm of mercury (Hg).  If so then 10 mm of mercury is about 0.193 PSI, so no they would not cancel out and the valve would stay shut.  If you wanted the direct opposite for PSI it would be Torr, so 10 PSI applied to one side of the valve and 517.1 Torr pulling it down, would equal out to zero.
Title: Re: Any maths guru's out there?
Post by: GeoffA on November 18, 2014, 09:37:15 PM
By hg, I assume you mean mm of mercury (Hg).  If so then 10 mm of mercury is about 0.193 PSI, so no they would not cancel out and the valve would stay shut.  If you wanted the direct opposite for PSI it would be Torr, so 10 PSI applied to one side of the valve and 517.1 Torr pulling it down, would equal out to zero.

That ^ is slightly at odds with your sig line Symon...... ;D ;D ;D
Title: Re: Any maths guru's out there?
Post by: neowatcher on November 18, 2014, 09:56:42 PM
The calculation for the numbe 5 is specified incorrectly. The exclamation mark is placed underneath the square root symbol, so it actually reads

SQRT(9x8x7x6x5x4x3x2x1) = 602 (approx)

And not the intended

(SQRT(9))! = 3x2x1 = 6

Title: Re: Any maths guru's out there?
Post by: Symon on November 19, 2014, 04:23:23 AM
That ^ is slightly at odds with your sig line Symon...... ;D ;D ;D

I thought it was pretty accurate actually ;D

The calculation for the numbe 5 is specified incorrectly. The exclamation mark is placed underneath the square root symbol, so it actually reads

SQRT(9x8x7x6x5x4x3x2x1) = 602 (approx)

And not the intended

(SQRT(9))! = 3x2x1 = 6

Well spotted!
Title: Re: Any maths guru's out there?
Post by: Garfish on November 19, 2014, 05:05:06 AM
You maths gurus might be able to help me ;D

With regards to psi and in hg, is one a linear form of the other, but in an opposite form of pressure? (That doesn't make much sense does it ??? )

Say if I had a mechanical force of 10 psi, applied to a valve, then added a 10 in hg vacuum to the same side of the valve, will this equal out zero?

Does that make sense?

Shane.


An inch of mercury is ~ .491 psi, you would need just over 20" of mercury to balance the 10 psi
Title: Re: Any maths guru's out there?
Post by: Footy Shorts Shane on November 19, 2014, 05:29:54 AM
By hg, I assume you mean mm of mercury (Hg).  If so then 10 mm of mercury is about 0.193 PSI, so no they would not cancel out and the valve would stay shut.  If you wanted the direct opposite for PSI it would be Torr, so 10 PSI applied to one side of the valve and 517.1 Torr pulling it down, would equal out to zero.

Thanks Symon, but by in hg, I was referring to inches of mercury. Probably should have put inHg shouldn't I,   :-\

An inch of mercury is ~ .491 psi, you would need just over 20" of mercury to balance the 10 psi

Thanks Garfish, that's exactly what I was after.  :cup:
That'll hopefully help me understand what's going on with a fuel pressure regulator I'm having some trouble with.

Thanks guys,   :cheers:

(Next problem. Don't suppose you guys have any experience with boost referenced fuel pressure regulators on twin turbo big blocks with a blow through set up do you ;D )
Title: Re: Any maths guru's out there?
Post by: speewa158 on November 19, 2014, 06:44:18 AM
RightO can we keep this thread in clear , simple Australian  so some can understand  :cheers: