Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**steewan****Guest**

My teacher gave me this problem and I can't figure it out.

Jn= J(n-1) + n, j=2

I've gotten:

j1 = 1

j2 = 2 + 2

j3 = 2+3+2

j4 = 2+4+3+2

J5 = 2+5+4+3+2

Did I do this right so far and is if so, where do I go from here?

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,520

What does j=2 mean?

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,242

Hi steewan;

Every recurrence must always have an initial condition. It appears that yours is J(0)=1. In which case J(2) is incorrect.

Also you are not computing that recurrence correctly.

where do I go from here?

Depends on what you are being asked to do. Were you asked to solve the recurrence? To plot it? To determine it's limit?

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

Offline

**scientia****Member**- Registered: 2009-11-13
- Posts: 222

steewan wrote:

My teacher gave me this problem and I can't figure it out.

Jn= J(n-1) + n, j

1=2I've gotten:

j1 =2

j2 = 2 + 2

j3 = 2+3+2

j4 = 2+4+3+2

J5 = 2+5+4+3+2Did I do this right so far and is if so, where do I go from here?

It's quite obvious that . Try verifying it by mathematical induction.

*Last edited by scientia (2012-11-06 11:12:49)*

Offline

Pages: **1**