2 years ago

the sum of the first n terms of a sequence is 20 - 10 / 2 ^ n - 1 find the sum of the first five terms

Mathematics

1 answer:

Travka [436]2 years ago

6 0

Answer:

$S_5=\dfrac{170}{9}$

Step-by-step explanation:

Given that,

The sum of first n term of a sequence is $S_n=20-\dfrac{10}{2n-1}$

We need to find the sum of the first 5 terms.

Put n = 5,

$S_5=20-\dfrac{10}{2(5)-1}\\\\=20-\dfrac{10}{10-1}\\\\=20-\dfrac{10}{9}\\\\=\dfrac{170}{9}$

So, the sum of first 5 terms is equal to $\dfrac{170}{9}$ .

You might be interested in

Which expression is equivalent to −1/ 12x−1 /3?

alexandr402 [8]

Answer:

$\frac{1}{12} (-x-4)$

Step-by-step explanation:

the expression we have is:

$-\frac{1}{12} x-\frac{1}{3}$

To find an equivalent expression, it would be helpful to express 1/3 so that it has a 12 in the denominator:

$\frac{1}{3}=\frac{4}{12}$

so we substitute this:

$-\frac{1}{12} x-\frac{4}{12}$

and now we have 1/12 in both terms :

$-\frac{1}{12}x-\frac{1*4}{12}$

so we can factor it (we take it out of each term: in the first we are left with -x and in the second with -4):

$\frac{1}{12} (-x-4)$

the equivalent expression is: $\frac{1}{12} (-x-4)$

5 0

3 years ago

A cereal box says that now it contains 20% more. Originally, it came with 20 ounces of cereal. How much cereal does the box come

Novosadov [1.4K]

Answer:24ounces

Step-by-step explanation:

Multiply 20 ounces by .20 (The percent) then add your answer to the 20 ounces.

6 0

2 years ago

What is the perimeter of a square with a side whose length is x + 4?

Novosadov [1.4K]

Answer:

4x+16

Step-by-step explanation:

Just multiply x and 4 by 4 to get your answer.

4 0

3 years ago

This is the least question of the day for me<br><br><br> Please help me :D

Rufina [12.5K]

Answer: i got 394

Step-by-step explanation:

3 0

2 years ago

BehaviorIsm qq oakqlqlwlskq

vagabundo [1.1K]

What the heck do you mean??????????

6 0

3 years ago

the sum of the first n terms of a sequence is 20 - 10 / 2 ^ n - 1 find the sum of the first five terms​

the sum of the first n terms of a sequence is 20 - 10 / 2 ^ n - 1 find the sum of the first five terms