Find a formula that generates a sequence

  • Thread starter nicnicman
  • Start date
  • #1
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Homework Statement



Find a formula that generates the sequence:

2/(3 x 4), -3/(4 x 5), 4/(5 x 6), -5/(6 x 7), . . .

Homework Equations





The Attempt at a Solution



Here is what I have so far:

a_n = -1(n/((n + 1)(n + 2)))

Now, I'm stuck. The formula generates a negative number every time. I need a negative number every other time.
Any suggestions?
 
Last edited:

Answers and Replies

  • #2
Dick
Science Advisor
Homework Helper
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Use something like (-1)^n?
 
  • #3
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Yeah, that will work. Thanks!
 

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