Math Is Fun Forum

steewan

Guest

Recurrence Relations and Backtracking

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: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Recurrence Relations and Backtracking

What does j=2 mean?

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“Here lies the reader who will never open this book. He is forever dead.
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The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Recurrence Relations and Backtracking

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?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

scientia

Member

Registered: 2009-11-13

Posts: 224

Re: Recurrence Relations and Backtracking

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

Jn= J(n-1) + n, j1=2

I've gotten:
j1 = 2
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?

It's quite obvious that

. Try verifying it by mathematical induction.

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