All categories

2 years ago

The sum of the first 15 terms of a geometric sequence with 7 as the first term and a common ratio of -3 is __________.

Mathematics

1 answer:

Andre45 [30]2 years ago

4 0

Step-by-step explanation:

the formula for the sum of the first n terms of a geometric sequence is

Sn = s1(1 - r^n)/(1 - r)

with r being the common ratio and s1 is the first term.

so,

S15 = 7×(1 - (-3)¹⁵)/(1 - -3) = 7×(1 - -14,348,907)/4 =

= 7×14,348,908/4 = 7×3,587,227 = 25,110,589

You might be interested in

What is the length of the cylinder's height? Please help

raketka [301]

Answer:

Height = 9 cm which means Option C is the answer

Step-by-step explanation:

In the question we are given ,

Volume of cylinder = 225π cm³

Radius of cylinder = 5 cm

And , we have to find the height of cylinder .

We know that ,

$\longrightarrow \pink{ \boxed{Volume \: of \: Cylinder = \pi r {}^{2}h }} \longleftarrow$

Our solution starts from here :

$\longmapsto \: \pi \: r {}^{2} h = 225\pi$

Step 1 : Cancelling π with π :

$\longmapsto \: \cancel{\pi} \: r {}^{2} h = 225 \cancel{\pi}$

Step 2 : Substituting value of radius which is 5 cm in the formula :

$\longmapsto \: (5) {}^{2} \times h = 225$

$\longmapsto \: 25h = 225$

Step 3 : Transposing 25 to right hand side :

$\longmapsto \: h = \frac{225}{25}$

Step 4 : Cancelling 225 by 25 :

$\longmapsto \: \red{\boxed{h = 9 \: cm}}$

Henceforth , height of cylinder is 9 cm

<h2 /><h2>#Keep Learning</h2>

8 0

1 year ago

Determine whether the data described are qualitative or quantitative:The weights of subjects in a clinical trial of a new drug.

Lynna [10]

Answer:

It is quantitative because they are looking at the weights which are numbers.

3 0

2 years ago

2. Solve for b in the linear equation 6b - 24 = 3(5b - 2)

Step2247 [10]

Answer: b = −2

Step-by-step explanation:

6 0

3 years ago

QUICK BEING TIMED

Snezhnost [94]

Answer:18

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Violet puts 12 out of every 192 dollars that she earns into a savings account. Which of the following is equivalent to

Paladinen [302]

Answer:

I think it is 12

Step-by-step explanation:

6 0

2 years ago