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Newbie
Bandwidth Hog
Joined: 23 Jan 2004
Posts: 2247
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 Posted: 25 Sep 2004 03:55:36 pm Post subject: |
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Does anybody know how to solve
{6+9x[7x+2(7+9X)+6]-9x+Y}
Without using the solve thing found in math on the calculator. I know the variables do not make it easy at all but theres gotta be a way to solve it, I hope. I also have problems typing problems like that without the variables, and I get an error.
Can someone solve this on a calc to simplyfy it? |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
Joined: 04 Nov 2003
Posts: 8328
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| Posted: 25 Sep 2004 05:03:48 pm Post subject: |
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1. I assume you mean "simplify" not solve because there is no =.
2. If you have multiple levels of parentheses they remain ( and ). For example,
(6+9X(7X+2(7+9X)+6)-9X+Y)
3. To simplify it use the Symbolic app from DS. There is no other good way to do it on a calculator, unless you have a TI-89.
4. If you have a TI-89, you just type it in. Make sure x,y are undefined, and beware of implied multiplication which does not always work: xy is not the same as x*y and x(y+z) is not x*(y+z) on a TI-89. |
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Arcane Wizard
`semi-hippie`
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Joined: 02 Jun 2003
Posts: 8993
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| Posted: 26 Sep 2004 04:33:21 am Post subject: |
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6+9X(7X+2(7+9X)+6)-9X+Y
6+9X(7X+14+18X+6)-9X+Y
6+63X²+126X+162X²+54X-9X+Y
6+(63X²+162X²)+(126X+54X-9X)+Y
6+225X²+171X+Y
Mind you I'm still half sleeping so I'm not sure it's correct.
And I don't have my calc anymore, gave it to my sister after graduating highschool since I wouldn't need it anymore and so my parent's wouldn't have to pay 100 euro's for another one.
Last edited by Guest on 26 Sep 2004 04:53:48 am; edited 1 time in total |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
Joined: 04 Nov 2003
Posts: 8328
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| Posted: 26 Sep 2004 01:59:38 pm Post subject: |
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| I think a program could be written to simplify a polynomial expression in terms of one variable easily. If you evaluate it at some large enough value like X=1000, you would get, for example, a value of 12024120225 for the polynomial 12X^3+24X^2+120X+225. |
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Brazucs
I have no idea what my avatar is.
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Joined: 31 Mar 2004
Posts: 3349
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| Posted: 26 Sep 2004 04:51:36 pm Post subject: |
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| While we're on the topic, does anyone know what the best factoring prog on ticalc is? There are so many... |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
Joined: 04 Nov 2003
Posts: 8328
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| Posted: 26 Sep 2004 05:07:47 pm Post subject: |
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| Write your own. I haven't checked but they probably all suck since no good programmer would bother releasing a program that takes less than 100 bytes. |
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Arcane Wizard
`semi-hippie`
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Joined: 02 Jun 2003
Posts: 8993
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| Posted: 26 Sep 2004 05:09:18 pm Post subject: |
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| What's a factoring program supposed to do? What I did in my post above? |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
Joined: 04 Nov 2003
Posts: 8328
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| Posted: 26 Sep 2004 05:12:26 pm Post subject: |
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No, like you put in 225 and it says 3*3*5*5.
Or if you put in X^2 + 2X + 1 and it says (X+1)(X+1). |
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Arcane Wizard
`semi-hippie`
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| Posted: 26 Sep 2004 05:23:43 pm Post subject: |
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| Hmm, I guess I'll stick to doing that manually in a second or so instead of breaking my head over how to write such a program (efficiently) for a couple of minutes and then going back to watching tv. |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
Joined: 04 Nov 2003
Posts: 8328
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| Posted: 26 Sep 2004 06:09:08 pm Post subject: |
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| Wasn't there a topic about really small factoring programs that were (presumably) pretty efficient? |
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Fr0sty
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Joined: 27 Nov 2003
Posts: 202
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| Posted: 26 Sep 2004 06:46:13 pm Post subject: |
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For a factoring program, just mod Benquad. It'd be about 1 kb if you take out all the extra crap in that program.
For the example 225 -> 3*3*5*5 you can just use OmniCalc. |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
Joined: 04 Nov 2003
Posts: 8328
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| Posted: 26 Sep 2004 06:50:54 pm Post subject: |
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Fr0sty wrote: For a factoring program, just mod Benquad. It'd be about 1 kb if you take out all the extra crap in that program.
1 Kb is way too much for a factoring program. |
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alexrudd
pm me if you read this
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Joined: 06 Oct 2004
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| Posted: 07 Oct 2004 05:16:20 pm Post subject: |
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Sir Robin wrote: 1 Kb is way too much for a factoring program.
Yeah, mines like 150 bytes and it took me maybe 10 minutes to perfect?
It isn't anything special, it just keeps dividing by increasingly large numbers and seeing if it divides evenly. Each factor is stored in the next spot of a list (So that you can use the list afterwards). It stops when the number = 1 or the dividend = square root of original number |
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aforsy
the leaping penguin
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Joined: 13 Jul 2004
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| Posted: 08 Oct 2004 11:49:50 am Post subject: |
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| or if the dividend equals the original number for primes! |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
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Posts: 8328
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| Posted: 08 Oct 2004 08:57:03 pm Post subject: |
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150 bytes? still too much really...
Input N
{1->L1
for(I,2,N
while not(fPart(N/I
N/I -> N
I -> L1(1+dim(L1
end
end
or something like this, haven't checked if this works. |
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alexrudd
pm me if you read this
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Joined: 06 Oct 2004
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| Posted: 09 Oct 2004 01:28:39 pm Post subject: |
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Sir Robin wrote: 150 bytes? still too much really...
Input N
{1->L1
for(I,2,N
while not(fPart(N/I
N/I -> N
I -> L1(1+dim(L1
end
end
or something like this, haven't checked if this works.
Yes, it works and it's much smaller than mine, but....
Factoring 2^10 took yours like 25 seconds, versus my 2 seconds. (I had a test for dividing by 2, so I could start at 3 later and only check odd numbers)
I optimizied mine for speed.  And I added stuff to make it easier. (no 1 as first list element, pauses for mirage, asks for number to factor)
To make it run faster, only test up to square root of N, as there can't be any factors higher.
Last edited by Guest on 09 Oct 2004 01:30:18 pm; edited 1 time in total |
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DarkerLine
ceci n'est pas une |
Super Elite (Last Title)
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Posts: 8328
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| Posted: 09 Oct 2004 01:52:20 pm Post subject: |
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Ack, it doesn't work the way it's SUPPOSED to. Apparently the For(1,2,N memorizes N so that changing N later doesn't affect the loop.
Code:
Input N
1->C
{Ans->L1
2->I
While 1
While not(fPart(N/I
N/I->N
I->L1(C
C+1->C
End
IS>(I,N
End
L1
72 bytes.
Oh, and just so you know testing with 2^10 is not a good way to test factoring programs. something like 337^2 would work better. |
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alexrudd
pm me if you read this
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Joined: 06 Oct 2004
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| Posted: 09 Oct 2004 02:15:48 pm Post subject: |
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Sir Robin wrote: Oh, and just so you know testing with 2^10 is not a good way to test factoring programs. something like 337^2 would work better.
I know, it's just that factoring multiples of two is where my prog is fastest. Wanted to make it look better in comparison. 
W/e, I'll used 237^2
Mine took 5 seconds
Your took over 1 min (stopped after that)
Haven't tested the new version though |
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alexrudd
pm me if you read this
Bandwidth Hog
Joined: 06 Oct 2004
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| Posted: 09 Oct 2004 02:20:02 pm Post subject: |
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| OK, your new version took 17 seconds.... |
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