Week 2 – Precalc 11

One of the things we learned this week in Precalc 11 is Geometric Sequences. It is a sequence of numbers where each term is found by multiplying the last term using the common ratio.

To find the common ratio, we can use the formula r=\frac {t_n}{t_n-1} dividing a term by the previous one.

Ex.
3, 6, 12, 24, 48,….
r=\frac {t_n}{t_n-1}
r=\frac {6}{3}
r=2

To find t_n we can use the formula t_n=a(r)^{n-1} Where a=t_1


The 10th term is 59,049.

To find n we can use the same formula.


6561 is the 8th term.

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