Maths problem 9999

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Originally Posted by Wongo

n! = n * n-1 * n-2 * n-3 * ....* 1

for example

4! = 4 * 3 * 2 * 1
1! = 1

By definition 0! = 1


9 + (square root 9)! + 9/9

= 9 + 3! + 9/9
= 9 + 6 + 1
=16

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thanx wongo, was wondering what that meant:2tsup:.

now i will know before every one else when we learn that later this year:D

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Originally Posted by Wongo

Sorry Greg, there were too many ((((((

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Starting to look like LISP code :cool:

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Originally Posted by Frank&Earnest

I still haven't cracked 67 though... does anybody know whether it is even possible?

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I tried it but couldn't do it. Sorry.

Thanks Wongo, once worked out that each 9 can be modified by symbols to make 1, 3, 6 and 9 I thought that maybe all integers could be made up with these four numbers, or something silly like that, but it appears that this hypothesis was too far fetched.:- So, again, back to woodworking!:U

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Originally Posted by Wongo

The "9 squared" bit is a bit dodgy.

What's next 9 thirded, 9 tripled or 9 minus five times four ?? :D

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I agree. Squared is the power of 2. That's got a 2 in it.

And Square Root is the Power to HALF......One on TWO:?:oo:

Sq Root is the Power to 0.5.....Same thing

The first post said "Use exactly four 9s and any number of arithmethic or higher level math operations." If the operation can be expressed by symbols without numeric terms it seems to be allowed: log (x), !, etc.

The issue here is whether to allow the symbol for square root because by convention the exponent 2 is omitted, while cubic root, for example, is not allowed because the exponent 3 must be written. The 9th root of nine, however, would have to be allowed, unquestionably, but it uses two of the four 9s allowed and is useless anyway.

We need to ask the third umpire.:D

:clap3: He got game.

I have a way to do it but I am not going to.

Consider

ln e = 1,

e/e = 1,

ln pi / ln pi = 1

pi / pi = 1

We can have number 1 without using any 9s. :2tsup:

But I won’t use it because it defects the purpose of this thread.

It is a bit like the stuff lawyers do. Legitimate but very very dodgy. :D

Here is another one

cos(pi) = -1

cos(pi) * cos(pi) = 1

:D

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Originally Posted by Wongo

Legitimate but very very dodgy. :D

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I beg to disagree.:) It is not a legitimate way because the "operation" is not performed on the four nines, it is performed on other numeric entities, albeit represented by symbols (pi, e, etc.). Have you found how to legitimately get 1 from only one 9?

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Have you found how to legitimately get 1 from only one 9?

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No bro.

I have been trying to do exactly that. If I could crack that I could crack 67. No luck so far.:doh:

infinite root of 9

Infinite root of 9 doesn't make it 1.

I think the real solution does exist though. The truth is out there.

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Originally Posted by Frank&Earnest

infinite root of 9

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Almost.

Zelk

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Infinite root of 9 doesn't make it 1.

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yes it does... you could write it as lim (x->infinite) of x root of 9, if you want to be that way...:D

limit is an approximation.:cool:

What is 9 divided by infinity then? Don't tell me it is 0.


:D

I guess you are one of those who still refuse to accept that 0.99999... recurrent is =1, then. You are fighting a rearguard battle, but if that's what lifts your boat...:p I'm not a good enough mathematician to follow you down that path.

Just to amuse me: assuming that you could get 1 from one 9, how do you get 67? It still baffles me.

Hang on mate!!
0.99999... is not 1. Why is it so hard to understand?

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Just to amuse me: assuming that you could get 1 from one 9, how do you get 67? It still baffles me.

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I have more than 1 way to do it but it is pointless so I won't show you. That will keep you thinking.... :U

Anyone wants to explain it? :D

https://www.woodworkforums.com/attach...1&d=1205219254

i'll take your word for it:cool:

Brilliant! :2tsup:Still illegal IMHO, though, for the same reason as before: the operation is not performed on the nines, in this case the nines only identify a subset of an unlimited, and therefore infinite, set of functions. If that were allowed, any and all numbers can be produced.

If, however, you have a solution that accepts the way I suggested of producing 1, I would still be keen to see it. We would then let the professors fight over it. (If you can still find any who champions your cause...:D) I have to admit that I do not have a great opinion of Adelaide academics, though, you might end up being right...:C

Well it is as illegal as the factorial. Both are mathematics notations not operators. We accepted factorial so we should accept summation too.

I think it is ok. Trust me.:cool:


I will let you know the other 2 ways when I remember them.:D

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Originally Posted by ss_11000

i'll take your word for it:cool:

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C’mon grasshopper. That is not the right attitude. :U

You need to work it out.

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Originally Posted by Wongo

Well it is as illegal as the factorial. Both are mathematics notations not operators. We accepted factorial so we should accept summation too.

I think it is ok. Trust me.:cool:


I will let you know the other 2 ways when I remember them.:D

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Hmmm.... As I always say to my daughter, never trust anybody who says "trust me"...:p

I still think that not being anally retentive about notations v. operators is OK (it reinforces my acceptance of lim x) , but does not change my point that you are working on infinite functions, not on the four nines, which denies the intention.

No worries mate. Take away both the ! notation and E notation. (sorry Greg, your solutions for 1 to 20 were wrong :D)

Re the acceptance of lim x, mate let me say it one more time 0.99999... is not 1.:cool: It's not even close.


:D

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Originally Posted by Wongo

Re the acceptance of lim x, mate let me say it one more time 0.99999... is not 1.:cool: It's not even close.


:D

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Well, tell that to my son's calculus professor... I'm too old for this... :C
You wouldn't still be stuck in Euclidean space, perchance?

It doesn’t matter if it is for a professor in calculus. 0.999999… is not equal to 1. It is a fact. You can round it up to 1 but it is not 1.

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Originally Posted by Wongo

C’mon grasshopper. That is not the right attitude. :U

You need to work it out.

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yeah sure.:rolleyes:

i'll let you know in a couple of months:2tsup:

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Originally Posted by Wongo

It doesn’t matter if it is for a professor in calculus. 0.999999… is not equal to 1. It is a fact. You can round it up to 1 but it is not 1.

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Do you accept that for any two numbers a and b there is an average number in between c = (a+b)/2?

No I don't

f

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Originally Posted by Wongo

Anyone wants to explain it? :D

https://www.woodworkforums.com/attach...1&d=1205219254

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Originally Posted by Wongo http://image-mirror.cyanide.com.au/w...2/viewpost.gif
C’mon grasshopper. That is not the right attitude. :U

You need to work it out.

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yeah sure.:rolleyes:

i'll let you know in a couple of months:2tsup:
__________________
S T I R L O :lbs:

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gday wongo, i just came across this thread again.

dunno if i'm right but does that (^^^) mean that the sum of the 3rd through to 6th terms of that series is 68, and minus the 1 it equals 67?:?


btw wongo, i got a headband that looks just like your avatar :D

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Originally Posted by ss_11000

dunno if i'm right but does that (^^^) mean that the sum of the 3rd through to 6th terms of that series is 68, and minus the 1 it equals 67?:?

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Correct

so how much sawdust is that in cubic metres?

sweet. :cool:

we learnt that stuff last term (sequences and series).

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Originally Posted by echnidna

so how much sawdust is that in cubic metres?

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1 cubic metre. :2tsup:


:U

Or would that be 9/9 + (9-9) cubic metres?:)

Sorry to dig up an old thread but I found this clock that some of you math-heads might enjoy.

http://geekswithblogs.net/ram/archiv...04/118249.aspx