Well this last unit was a good one to leave off on. I actually had and am still having a little bit of trouble with the homework because I keep mixing up which formula's are used for what and what goes where within them. But with the blog open in front of me it's not that bad. I'll have it pegged by tomorrow. But just to clarify...

To find a term in an arithmetic sequence:

tn = t1 + (n -1) * common difference

(I used t1 because that "a" confused me for a good long while, had no meaning for me)

To find a term in a geometric sequence:

tn = t1(common ratio)^(n-1)

To find the sum of the terms in an arithmetic series:

Sn = (n/2)(2t1+(n -1) * common difference)

or

Sn= n(t1 + tn)/2

To find the sum of the terms in a geometric series:

Sn = (t1(1-r^n))/(1-r)

To find the sum of the terms in an infinite geometric series:

Si = t1/(1-r)

So I'm going to finish up my homework now.

byebye

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## 1 comment:

thanks for the reminders/clarification Graeme!

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