Question

Find S12 for the series 1 + 2 + 4 + 8 +...

Answer 1

\(\Large \color{Black}{\Rightarrow 2^{n -1} }\)
Is the formula.

\(\Large \color{Black}{\Rightarrow 2^{12 - 1} }\)
In this case.

Answer 2

What is 2^11.
1024 * 2
2028

Answer 3

Do we have to find the sum or what?

Answer 4

mo just the S12 of the sequence

Answer 5

Then you have it :P

Answer 6

2028?

Answer 7

2048*

Answer 8

but why did you put 2^11 when it should be S12?

Answer 9

:S

Answer 10

Because S1 is 2^0
S2 is 2^1
S3 is 2^2
So it's one less power.

Answer 11

I think it's the sum

Answer 12

okay

Answer 13

I see the plus signs.
The sum would be:

\(\Large \color{Black}{\Rightarrow 1 \times {1 - 2^{12} \over 1 - 2 } }\)

Answer 14

2 is r
12 is n.

Answer 15

1 is a(the first term)

Answer 16

The general formula is
\[\frac {a(r^n -1)}{r-1}\] for r>1,r<-1
\[\frac{a(1-r^n)}{1-r}\] for -1<r<1