All categories

4 years ago

Find S9 for the geometric sequence: an=2∙5n−2 Please show work

Mathematics

1 answer:

Anika [276]4 years ago

8 0

Answer:

I guess that the geometric sequence is:

An = 2*5^(n - 2)

we usually have that that a geometric sequence is something like:

A*r^n.

so i will write the first two terms of our sequence separated, and i will calculate the summation of the first seven terms after n = 2.

A0 = 2*5^(-2) = 2/25

A1 = 2*5^-1 = 2/5

Then, the sum for a geometric sequence is:

SN = A(1 - r^N)/(1 - r)

in this case, A = 2 and r = 5, and i will use N = 7 for the sequence 2*5^n

S7 = 2*(1 - 5^7)/(1 - 5) = 39,062.

now we add the first terms that we obtained before and get:

S9 = 2/25 + 2/5 + 39,062 = 39,062.48

You might be interested in

If a and b are rational numbers and 6/(3√2-2√3 ) = a √2-b √3 , then find the values of a and b.

eduard

Answer:

=3–√−13–√+1⋅3–√−13–√−1

=(3–√−1)23–√2−12

=3–√2+12−23–√3−1

=4−23–√2

2−13–√

a=2,b=−1.

Step-by-step explanation:

6 0

3 years ago

Which functions has the fastest rate of increase?

Mashcka [7]

The function with the higgest rate of increase is 2^x

6 0

3 years ago

HELP ME PLEASE! ILL MARK U BRAINLIEST IF U ANSWER ALL THE QUESTIONS

levacccp [35]

Answer:

Step-by-step explanation:

For which of the following counts would a binomial probability model not be reasonable? a)the number of people in a classroom born in januaryb) the number of people in a classroom with red hair c) the number of people admitted to a hospital in a day with a particular disease d) the number of heart beats in a one-minute perio.The population of a small rural town in the year 2006 was 2,459. the population can be modeled by the function below. residents and t is the number of years elapsed since 2006 f(3) = 2,459(0.32)

Answers: 3

Hope this answer helps you :)

Have a great day

Mark brainliest

5 0

3 years ago

Would any of you happen to know this one?

Nikitich [7]

274.80 if you rounded to the nearest 10th but if you don’t it will be 274.78

3 0

3 years ago

Can someone help with my homework?

Len [333]

Answer:

1a) $-\frac{15}{4}$

1b) $\frac{95}{33}$

2a) $-84$

2b) 1

3a) $\frac{171}{550}$

3b) $4\frac{2}{7}$

Step-by-step explanation:

For the first equation, let's use $\frac{-a}{b} =\frac{a}{-b} =-\frac{a}{b}$ to right a new fraction.

Step 1- Reduce the fraction with 4.

$-\frac{\frac{12/4}{4/4} }{\frac{4}{5} } = -\frac{3}{\frac{4}{5} }$

Step 2- Simplify the complex fraction(LCD or Least Common Denominator).

$-\frac{3}{\frac{4}{5} } = -\frac{15}{4}$

An alternative form for this fraction is $-3\frac{3}{4} or -3.75$ .

For the second equation..

Step 1- Convert the mixed number to an improper fraction.

$\frac{6\frac{3}{9} }{\frac{11}{5} } = \frac{\frac{57}{9} }{\frac{11}{5} }$

Step 2- Simplify the complex fraction.

$\frac{\frac{57}{9} }{\frac{11}{5} } = \frac{95}{33}$

An alternative form for this fraction is $2\frac{29}{33} or 2.87$ .

For the third equation use $\frac{-a}{b} =\frac{a}{-b} =-\frac{a}{b}$ ...

Step 1- Simplify the complex fraction(LCD).

$-\frac{7}{\frac{1}{12} } = -84$

For the fourth equation...

Write the fraction as a division.

$\frac{12}{8}$ ÷ $\frac{3}{2}$

To divide a fraction, multiply by the reciprocal of that fraction.

$\frac{12}{8} *\frac{2}{3} = \frac{12*2}{8*3}$

Reduce the fraction with 3.

$\frac{4*2}{8}= \frac{4}{4} = 1$

For the fifth equation...

Convert the mixed number to an improper fraction.

$\frac{-1\frac{8}{11} }{-5\frac{5}{9} } = \frac{-\frac{19}{11} }{-\frac{50}{9} }$

Reduce the fraction with -1, this eliminates the negative sign.

Simplify the complex fraction.

$\frac{\frac{19}{11} }{\frac{50}{9} } = \frac{171}{550}$

An alternative form for this fraction is 0.3109.

For the sixth equation..

Write the fraction as a division.

$\frac{3}{7}$ ÷ $\frac{1}{10}$

To divide by a fraction, multiply by the reciprocal of that fraction.

$\frac{3}{7}$ ×10= $\frac{3*10}{7}$

Multiply the numbers.

$\frac{3*10}{7} = \frac{30}{7}$

Alternative form of this fraction is $4\frac{2}{7}$ or 4.285714.

Hope this helps! :)

8 0

3 years ago