EPT1 , 12 , 123 , 1234 , 12345
What models this?
I've been thinking for like 1/2 hour.
math sequences question
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kdog3683
United States916 Posts
1 , 12 , 123 , 1234 , 12345 What models this? I've been thinking for like 1/2 hour. | ||
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Myrmidon
United States9452 Posts
f[n] = 10*f[n-1]+n 3rd number is 10*12+3 = 123, 4th number is 10*123+4, etc. Hopefully the awkward notation (I forget the actual) is clear. | ||
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aeronexus
United States392 Posts
 guess my math ain't what it used to be, seeing how I'm an English major now XD | ||
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Equinox_kr
United States7395 Posts
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sigma_x
Australia285 Posts
such that "n" is a positive integer and f(1)=1 | ||
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Equinox_kr
United States7395 Posts
On April 11 2008 12:58 sigma_x wrote: f(n) = -10/81+10/81*10^n-1/9*n such that "n" is a positive integer and f(1)=1 can't believe you registered on TL just to say that rofl | ||
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sigma_x
Australia285 Posts
i've been browsing tl.net for a few years now but finally decided to get an account a week or so ago... | ||
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xhuwin
United States476 Posts
On April 11 2008 13:10 Equinox_kr wrote: can't believe you registered on TL just to say that rofl ROFL. Hahaha that made my day. How did you find the explicit definition though? | ||
mikeymoo
Canada7170 Posts
On April 11 2008 13:10 Equinox_kr wrote: can't believe you registered on TL just to say that rofl I find this phenomenon quite often in homework help blogs. We shall call this the FPHH Theorem (First post homework help) | ||
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sigma_x
Australia285 Posts
 i thought i'd make myself useful... sheesh. It breaks down at n=10 of course. Refer to "Solving non-homogeneous recurrence relations" on wikipedia for help. It involves solving the linear recurrence solution first which is f(n)=10f(n-1) and then guessing a solution for the non-linear part.Edit: http://en.wikipedia.org/wiki/Recurrence_relation#Solving_non-homogeneous_recurrence_relations | ||
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oneofthem
Cayman Islands24199 Posts
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oneofthem
Cayman Islands24199 Posts
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artofmagic
United States1951 Posts
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mikeymoo
Canada7170 Posts
On April 11 2008 13:35 sigma_x wrote: i thought i'd make myself useful... sheesh. It breaks down at n=10 of course. Refer to "Solving non-homogeneous recurrence relations" on wikipedia for help. It involves solving the linear recurrence solution first which is f(n)=10f(n-1) and then guessing a solution for the non-linear part.Edit: http://en.wikipedia.org/wiki/Recurrence_relation#Solving_non-homogeneous_recurrence_relations Oh don't take it wrong. I'm not dissing you, I'm commending you. (No sarcasm) | ||
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thunk
United States6233 Posts
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fight_or_flight
United States3988 Posts
On April 11 2008 13:10 Equinox_kr wrote: can't believe you registered on TL just to say that rofl proof that homework threads are awesome | ||
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