Question

What is the 20th term of the sequence that begins −3, 6, −12, 24 ...?

Answer 1

@whpalmer4

Answer 2

@Mertsj

Answer 3

It is a GP......
Here a=-3,common ratio r=-2
There fore using the eqn.,
20th term of the sequence =a(r)^(n-1)=-3 * (-2)^19=-1572864

Answer 4

Just keep multiplying y -2 until you get the 20th term. That's the easy way. Or you could use your formula.

Answer 5

Got it!!!!

Answer 6

@xkylex

Answer 7

\[a _{20}=a _{1}r ^{20-1}\]

Answer 8

Mertsji, using your formula, would I get the same result as ashwinjohn3?

Answer 9

yes. He used the same formula

Answer 10

Ok. Thanks all of you!

Answer 11

yw