10.2 Flashcards
What is the general form of a geometric series
The summation from 1 to infinity of ar^(n-1)
How do you determine the convergence of a geometric series?
If -1<r<1 then the series converges to a/(1-r) where a is the first term. If |r|>=1, the series diverges
What does the nth term test say
A series from 1 to infinity of an diverges if the limit as n approaches infinity of an fails to exist or is different from zero. This does not mean that all series with limit 0 converge.
∑(an+bn)
A+B
∑(an−bn)
A-B
∑kan
kA
If ∑an converges and ∑bn diverges, what can be said about ∑(an+bn) and ∑(an-bn)
Both diverge. This is not necessarily the case if both diverge, only if one does.
How do you raise the starting value of n of a summation?
Replace the starting point of the summation with (1+h), and the value of n in the summation with (n-h)
How do you lower the starting value of n in a summation?
Replace the starting point with (1-h), and the value of n in the formula with (n+h)
What is the sum of an alternating geometric series with |r|<1?
a/(1+r)