Question

When answering questions 1–6, please separate your answers with a semicolon (;).

For questions 1–6 determine whether each series is arithmetic or geometric. Then evaluate the series to the given term.

1. 1 + 3 + 9 + ...; S8

2. 5 + 7 + 9 + ...; S8

3. 25 + 32 + 39 + ...; S12

4. 256 + 192 + 144 + ...; S7

5. 1 – 3 + 9 – 27 + ...; S10

6. –14 + (–7) + 0 + 7 + ...; S10

Answer 1

@Ket-kat this is the one

Answer 2

1. + 3 + 9 terms .............upto 8

The given series is geometric series like a, ar, ar^2, ---------- where a is first term and r is common ratio.

The sum of n terms in geometric series is given by, Sn = a(r^n - 1)/(r - 1)

Here a = 1, r = 3 and n = 8

S8 = 1(3^8 - 1)/(3-1)

= (6561 - 1)/2

= 3280

Answer 3

2. arithmetic
96

Answer 4

3.arithmetic
add by 7

Answer 5

4.geometric

5.geometric

6.arithmetic

Answer 6

@Ket-kat keep going and i'll give you a medal(: thanks this really helps!

Answer 7

@Ket-kat Thanks (: but u forgot to evaluate the series to the given term for some of them