Mathematics Thread

[cmhardw]

silly thing:

take 922 digits of pi, including the 3 at the start
remove the decimal point
replace all the 0s with 69
congralutations you have a prime number

Spoiler

3141592653589793238462643383279569288419716939937516958269974944592369781646962862698998628693482534211769679821486986513282369664769938446699556958223172535946981284811174569284169276919385211695559644622948954936938196442881699756659334461284756482337867831652712691969914564856692346693486169454326648213393669726692491412737245876969666963155881748815269926996282925469917153643678925969366969113369536954882694665213841469519415116699433695727693657595919536992186117381932611793169511854869744623799627495673518857527248912279381836911949129833673362446965664369866921394946395224737196976921798669943769277695392171762931767523846748184676694695132696969568127145263566982778577134275778966991736371787214684469969122495343691465495853716956979227968925892354269199561121296921966986469344181598136297747713699966951876972113499999983729786949951695973173281669963185956924459455346969836926425223698253344685693526193118817169169696931378387528865875332698381426961717766914736935982534969428755468731

Cool! How did you discover this? Were you looking for the first n digits of pi where this substitution would (hopefully) work? That substitution seems oddly specific

 

[10461394944000]

Cool! How did you discover this? Were you looking for the first n digits of pi where this substitution would (hopefully) work? That substitution seems oddly specific

yeah, pretty much, me and soup have found lots of silly primes recently. examples:

that one

Spoiler: first 194 digits of pi, then replace all the 5s with 4s and the 4s with 5s

31514926434897932385626533832794028851971693993741048209759554923078165062862089986280358243521170679821580864132823066570938556094404822317243495081285811175402851027019384211044496556229589459

Spoiler: 69 and a 7

69696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696969696967

Spoiler: first 10 digits of e and pi repeated a lot

2718281828271828182827182818282718281828314159265331415926533141592653314159265327182818283141592653271828182831415926533141592653314159265327182818283141592653271828182831415926533141592653314159265331415926532718281828271828182831415926532718281828314159265331415926533141592653271828182831415926533141592653314159265327182818283141592653271828182831415926532718281828314159265327182818282718281828314159265327182818282718281828271828182831415926533141592653271828182831415926533141592653314159265327182818282718281828314159265331415926533141592653271828182827182818282718281828314159265327182818283141592653271828182827182818283141592653314159265331415926533141592653314159265331415926532718281828271828182831415926532718281828314159265331415926532718281828314159265331415926532718281828271828182831415926532718281828314159265327182818282718281828314159265331415926532718281828271828182831415926532718281828314159265327182818283141592653271828182831415926533141592653314159265331415926533141592653

Spoiler: thing with ~90% 3s and ~10% 7s

33337333333333333733373373333337333333333333333733333733333733733333333333333733733333373337333333333333333733333337333333337333333333333333333373337333333333333333333333333333333733333333333333373373373337333333333333333373333333733333333333733333333333333373337333333333333333333373373333373333333733733333333333333333333333333333733333333373773373733333733333333333333333333333333333733333373333333333333333333333337333333733333337373333333333333333333333333337733733373333333333333333333333333333333333373333337377777373333333333333333333333333333333333333733333333373333333733333333333333337333333333333333333333373333333733333333733373333333333333333337337333333373333373337333333337733733333333333333733333333333333333733333333733333333737373333333337733333333333333373333333333333333333377337333333373333377333333333333733333337333333333377733333333333333333373333373333373333333333333333333333333373333333333337333333337333333333333333773333777333333333333733333333333333333333333373333333333733733373333333733333333333333333333333733333373333333333333337333733373333373333733733337333333333373333333333333333333333333333333333333333333773373333333333333333373333333333333333333333333333333333373333337333333333733333333333333733333733733333333333333333733333333333333333333333333333337333333333333337333333333373333333333333333373333333773373373333333333333333333333333333733333733733333333333333333737333337333333333333333377333373333333333333333333333333733333333333333333333333333333373333733733333333333333337333333333373373337333333333337333333333333333373337333373333333333333373337733333333333333333373337333733333333733333333333333333333333333733333333733333333333333333333333333733733333333333337333333733333333333333333333373333333333333333373333333373333337333333733333773333333373333333333333733333333773333333333333337333337333333333333333333333333333333333337333333333373337377333733333333333337333333737377333333333333333333337373733333333333373333733733333733377333333733333

Spoiler: prime made of square numbers with 0s between them

90002500081000360003600064000900081000640004900049000360008100025000100010004000810004000160001000160001600025000360008100010002500010004000160009000810003600025000900049000250009000250006400036000640001600025000100064000100064000160008100025000160006400016000160004900016000360006400090001600081000400040001600064000640004900049000160001000900016000360003600025000490008100016000400036000490004000810001600064000160004000100064000160003600025000640001600064000360006400081

Spoiler: prime made of primes with 0s between them

970110730710301703101304705301708905301907102901902037050470304304707903108304108902907108301902017030670301301902307304107304109703704707073067070610610670207302089017053047089073030230610301309704705905304708905906102903011070502905907305067011047067070208303709708309704101906707303103097041011071047053073047017070610530706107104706708306707097020970830304105097041050170310110310110370470730110207105017041017059073071073053097037089070590710470430190310190410530970790130230470310710670590670430290230707106707305303041053017023041073011029031047020530203101102020370710190410830290730507906708307905906105059020610130207031011079031061029041070110590701307104301102903702305307901703030370110410709707073017050590410710830708901706108305905301101101105070830790530610670670670310110670370230530890208905304307104303706701102020505043097043011097070710890830530370370230110110170590110410501907029050470410530170507907104707306707101307908304702305050970130502061079059083031019071019019011030790130110470710501707104101703107103053089011029020208902061071011067071070610830710430590370290730610230470410710710130501901304704703708307905908303073030290230290230530190190290830370730170170303108305037073013071061061019070410530207023089023071031053047041017041059029020410410890501301904305017037097043079037097079030710970830310290790206702043070610430190310290410509701706104702904104702023071097059017

Spoiler: only containing 1 2 and 3

2313131231321223131221333123132123323233132313322321323231121312231113311223232211313313123221132123232212233123233321221111111221113313322312122311121323333231322312311232211222211232121222121231332332132213133333111121322223311313133332221133123212333111221113232322333111331232112211323112323331331331213333232113223121131232212311123331331132311212231231233312112321312121323123331122132132333333313322122113313211321232123321132122123333112321223311123321112131311221312223333132313123121111332322233312112311312323132233313111121122123222232323312331212121113321111233322113212313232332213123311131222323333222232222133133321331132323112133111112221233232122111323311323122312321223312212332113132113111132133212321312221211312122221132311311313231312122122112311232213333311332121233212323132323311131123133213213111113121211122211113332223112222333221213113332231211321222323113123113112231223231111333231122223213231113312333131133321323233221213222212322313332311231111132131112331123321333

Spoiler: lolololol 69 leet

133769696969133769691010101011337691337133710101010169133713371337691010101016913371010101011010101011010101011010101011010101011337133713371010101011337133710101010110101010169133713371337691010101016910101010169101010101133713376969691010101011010101016910101010169101010101133769133710101010110101010113376969101010101696910101010110101010110101010169133713371010101016969691010101011010101011010101011010101011010101011010101016910101010169133710101010169691337101010101696969133769691010101011337133769133710101010169133769696913371337691337101010101696969691010101016969133710101010113376969133713376969691337691010101011337696969691337133710101010113371010101016913371010101011010101016913376910101010169101010101101010101696913371010101016910101010110101010169101010101691010101011337691337101010101133713371010101016913371010101011337101010101133713376913371010101011337133713371010101011337691010101016913371010101016910101010169691337133710101010169696913371337691337133713371337101010101133710101010169101010101691337133710101010110101010113371337101010101696913376913371010101016969691337133710101010110101010169696910101010110101010169133710101010113371010101011337133769133710101010113371010101016913376910101010169696910101010110101010169101010101691010101011337101010101133710101010110101010113371337691337133769101010101133769101010101691337133710101010169133713376910101010110101010169696910101010110101010110101010169133769133710101010110101010110101010169101010101696913371010101011337101010101691010101011337133713371010101011010101011337133769101010101101010101133769696910101010110101010169101010101133710101010110101010169133713371010101011337101010101691337133713376969101010101101010101133769133713376913371337101010101696969691010101011337101010101101010101133710101010110101010110101010169133710101010169133713371010101016913371010101011337101010101691010101011010101011010101016969101010101691337133710101010113371337133710101010169133713371010101016913371337101010101696913371337101010101691010101016910101010113371010101011337691010101011010101016969133769133710101010110101010169133710101010169101010101691337691337101010101133710101010113376910101010169691010101011010101011337133710101010169101010101133769133710101010113376910101010113376913371010101011010101016969101010101691010101011010101011010101011010101011010101011010101011337101010101133710101010113376969696913371337101010101691337101010101691337696969696913371337133713371010101011337

Spoiler: alot of 7s and a 1

7777777777777777777777777777777777777777777177777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777

Spoiler: 1357 and 2468

135724682468135724682468135724682468135724682468135713572468135724681357135724681357246824681357246824681357246813571357246824681357246813572468246813571357246824682468246813571357246813571357135713571357246824681357135713572468135724681357135724682468246824681357246813571357246824681357246824681357135713571357246824682468246813572468246813571357246824682468135724682468135713572468246813571357135724682468246824682468135724681357135713571357135713572468246813571357135724682468246813572468135724681357135724682468135713571357246824681357246824682468246824682468135724682468246813571357135724682468246813572468246824682468135724682468246813571357246813572468246813571357135713571357246824681357246813572468135724681357246813572468135713572468246813572468246813572468246824682468135713572468246824682468135724682468246813572468135724681357246824682468246824681357246813571357135724681357246824682468135713571357135724682468246813572468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824682468246824681357246824681357246813572468246824681357

Spoiler: 1 and 123456789

1123456789123456789112345678912345678911234567891234567891123456789123456789111234567891123456789111234567891123456789123456789112345678912345678911234567891112345678912345678911234567891123456789123456789111234567891234567891234567891234567891112345678911111123456789123456789111123456789112345678911123456789123456789123456789123456789112345678911123456789123456789112345678912345678911111234567891234567891234567891234567891123456789123456789111234567891234567891234567891123456789123456789111234567891234567891111234567891234567891234567891234567891234567891123456789111111123456789123456789111123456789123456789123456789112345678911234567891112345678912345678911112345678912345678911234567891234567891234567891234567891234567891234567891123456789123456789123456789111123456789123456789123456789112345678912345678912345678912345678911234567891234567891234567891112345678911234567891234567891111112345678912345678911234567891123456789112345678911234567891123456789111234567891234567891123456789123456789112345678912345678912345678912345678911123456789123456789123456789123456789112345678912345678912345678911234567891123456789112345678912345678912345678912345678912345678911234567891111234567891123456789123456789123456789111112345678912345678912345678912345678911111111111111111111111111111111111111111111111111111111111111111111111111111111111111111112345678912345678912345678911234567891123456789123456789123456789123456789

Spoiler: mostly 1s with afew 7s

1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111717771117

Spoiler: 0 and 123456789

1234567890012345678900123456789001234567890012345678912345678901234567890123456789123456789012345678900123456789001234567890123456789123456789001234567890123456789001234567891234567890000123456789123456789012345678912345678912345678912345678912345678900123456789123456789123456789012345678901234567891234567890000123456789012345678912345678900123456789001234567891234567891234567891234567890000123456789001234567891234567890001234567890012345678912345678900123456789123456789123456789000001234567890123456789123456789123456789123456789123456789123456789001234567891234567891234567890001234567890123456789012345678912345678900123456789123456789123456789001234567890000001234567890001234567891234567891234567890001234567890000123456789000123456789123456789012345678900123456789123456789123456789123456789123456789001234567890123456789012345678901234567890123456789012345678912345678900123456789001234567890000123456789123456789000012345678900012345678901234567890123456789000001234567890123456789123456789123456789012345678900012345678912345678912345678912345678900001234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567891234567890000123456789123456789123456789001

10^2000 + 10^1515 + 10^731 + 10^357 + 1
10^5076 + 7
10^2067 + 3
(998*1006!)^2 + 1

soup just found 218707*2^88670 +1 about an hour ago which is a lot bigger than all of those (26699 digits)

 

[goodatthis]

Took my algebra 2/trig regents (ny state exam) a week ago, would have gotten a 98 if it weren't for me forgetting that 0 occurrences is a possible probability for one of the questions, and if my calculator wasn't in freaking radians for the last, 6 point question. Stupid. Still got a 94 though, and it's considered a very hard test, so I'm happy.

 

[10461394944000]

ok jus done step2 and it was weryhard

 

[cmhardw]

yeah, pretty much, me and soup have found lots of silly primes recently. examples:

that one

...

Neat!

How are you testing primality of these numbers? Are you using software to try to factor them? Are you using number theory and primality tests?

I've always liked this site for factoring. Are you using this site, or something like it?

 

[10461394944000]

Neat!

How are you testing primality of these numbers? Are you using software to try to factor them? Are you using number theory and primality tests?

I've always liked this site for factoring. Are you using this site, or something like it?

1 line of mathematica code

 

[qqwref]

What font size would you need for the word "SMILES" to actually have a mile between the two S's? Assume Verdana.

 

[TDM]

What font size would you need for the word "SMILES" to actually have a mile between the two S's? Assume Verdana.

any
E: well anything bigger than 0

 

[rebucato314]

The hardest thing i learnt in maths is intergration. (in calculus)

(btw I'm 11)

 

[ryanj92]

I do physics, so I need to be fairly sharp with my maths also. Especially seeing as I like all the theoretical stuff so I need the maths to be able to understand it...

I answered 'equations' because of differential equations I think the fiddliest maths I've had to do so far was for an applied maths-type module I did last year, where we solved ODE's using series solutions. I screwed up the question on it in the exam - keeping track of indices is difficult

 

[cmhardw]

Has anyone else had issues with LaTeX with the \lfloor, \rfloor, \lceil, and \rceil tags in [noparse]\( [/noparse] mode? \)

 

[Christopher Mowla]

Has anyone else had issues with LaTeX with the \lfloor, \rfloor, \lceil, and \rceil tags in [noparse]\( [/noparse] mode? \)

\( I've had problems recently as well. About a month ago, at least, LaTeX worked sometimes and sometimes it didn't.

I have used http://sciencesoft.at/latex/?lang=en to print out very large formulas (since there is a limit on the number of characters with LaTeX on this site), and thus I use that to create images and then I upload them on the web whenever the LaTeX is down on this site.

To use that online tool,
[1] Click the blue "Example" button.
[2] Delete all generated text between the line of text "% Birkhäuser Boston 1996 entnommen" and "\end{document}".
[3] Type your latex in between those two lines in AMS-LaTeX form.
[4] Click the "Start LaTeX" button.

For example, to create \( \left\lfloor \frac{n-2}{2} \right\rfloor \),

Instead of <math>\left\lfloor \frac{n-2}{2} \right\rfloor </math>
type:
\[
\left\lfloor {\frac{{n-2}}{2}} \right\rfloor
\]

(I just use MathType Equation Editor to translate for me.). \)

 

[TDM]

Anyone else do the senior maths challenge today?

 

[JediJupiter]

Anyone else do the senior maths challenge today?

Hell yes! I didn't answer the first question in section 2 and that one about the cube that she drew an "unbroken" line on I got wrong, because I thought the end and beginning had to join up but they didn't...

 

[TDM]

Hell yes! I didn't answer the first question in section 2 and that one about the cube that she drew an "unbroken" line on I got wrong, because I thought the end and beginning had to join up but they didn't...

Yeah, I thought that at first too... I think I eventually decided, for some reason, that would make the line have an infinite length (not sure why I thought that ), so it couldn't join up. I think the answer was four of the long straight lines and two of the shorter diagonal ones... can't really remember
What did you get?

 

[JediJupiter]

Yeah, I thought that at first too... I think I eventually decided, for some reason, that would make the line have an infinite length (not sure why I thought that ), so it couldn't join up. I think the answer was four of the long straight lines and two of the shorter diagonal ones... can't really remember
What did you get?

I can't remember? I think it was four diagonal ones and two straight across. Good luck getting into the next round! Are you doing the team maths thing too?

 

[TDM]

I can't remember? I think it was four diagonal ones and two straight across. Good luck getting into the next round! Are you doing the team maths thing too?

Thanks! I think I did get into the next round; I got 110... even though I got question 5 wrong :fp
Yeah, I'm doing the team maths challenge as well. It's going to be at our school, so we're supposed to have two teams doing it, but we could only find 4 people who actually wanted to do it

 

[JediJupiter]

Thanks! I think I did get into the next round; I got 110... even though I got question 5 wrong :fp
Yeah, I'm doing the team maths challenge as well. It's going to be at our school, so we're supposed to have two teams doing it, but we could only find 4 people who actually wanted to do it

It sucks that you could only find 4, we already had ours and we came 4th which was pretty good.

 

[TDM]

It sucks that you could only find 4, we already had ours and we came 4th which was pretty good.

Oh nice. Does 4th get you through to a later round?

 

[JediJupiter]

Oh nice. Does 4th get you through to a later round?

You pretty much need to come first and sometimes they let you through if you're second, so sadly no, but out of 30 it's definitely a good result.