Step-by-step explanation:
sum of the arithmetic sequence
a1 = 8
a2 = a1 + 8 = 8+8 = 16
...
an = 8×n
the sum of the first n elements of such a series is
n/2 × (2×a1 + (n - 1)×d]
with d being the difference between 2 consecutive elements (= the added constant).
so,
s30 = 30/2 × (2×8 + 29×8) = 15×(31×8) = 3720
Answer:
Step-by-step explanation:
a1 = - 2
an = a1 * r^(n - 1)
a6 = -486
-486 = - 2 * r^(6-1) Divide by 2
243 = r^5
The largest value that r could be is 3.
4^5 = 1024
(243)^(1/5) = 3
So the general formula
an = -2*(3)^(n - 1)
If 3.14 is rational, why should pi also be rational ?
The answer to your question is: Because pi is not 3.14 .
