3 years ago

Find S8 for the geometric series 3 + -6 + 12 + -24 +…

1 answer:

6 0

I guess you are asking to find the sum of the first 8 terms. If so, then:
Sum = a₁(1-rⁿ)/(1-r), where a₁ is the 1st term, r=common ratio and n=number of terms:
the 1st term a₁ =3
common ratio r = - 2 (since -6/3 = - 2, and 12/-6 = - 2, etc.)

Sum = 3[(1- (-2)⁸]/(1-2) = 3(1- 256)/(1/2)
Sum = -1530

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Multiply 72.22 and 4.1

viktelen [127]

Answer: 316.52

Step-by-step explanation:

77.2*4.1 = 316.52

If you have problems with multiplying decimals:

Multiply the numbers just as if they were whole numbers.

1.Line up the numbers on the right - do not align the decimal points.

2.Starting on the right, multiply each digit in the top number by each digit in the bottom number, just as with whole numbers.

3.Add the products.

4 0