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bija089 [108]
2 years ago
5

PLEASE HELP!! 50 POINTS!! If you're not going to help, please don't answer.

Mathematics
1 answer:
Dimas [21]2 years ago
7 0

Part A

A geometric sequence is where the terms increase by the same ratio.

Example:

7, 14, 28, 56, ...

We start at 7 and double each term to get the next term. The common ratio is 2.

============================================================

Part B

The next step is to subtract the two equations straight down. This will cancel the vast majority of the terms, and allow to solve for S_n to get a fairly tidy formula. Refer to part C for more info.

============================================================

Part C

S_n = a_1 + a_1r + a_1r^2 + \ldots + a_1r^{n-1}\\\\rS_n = a_1r + a_1r^2 + \ldots + a_1r^{n-1} + a_1r^n\\\\rS_n - S_n = \left(a_1r + a_1r^2 + \ldots + a_1r^{n-1}+a_1r^n\right)-\left(a_1 + a_1r + a_1r^2 + \ldots + a_1r^{n-1}\right)\\\\S_n(r - 1) = a_1r^n - a_1\\\\S_n = \frac{a_1r^n - a_1}{r-1}\\\\S_n = \frac{-a_1(r^n - 1)}{-(-r+1)}\\\\S_n = \frac{a_1(1-r^n)}{1-r}\\\\

For more information about the canceling going on from step 3 to step 4, see the attachment below.

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Answer:

y - 3= 2(x - 0)  

Step-by-step explanation:

hello :

note 1 :

the point-slope formula is :

y - y_1 = m(x - x_1)   the point is A(x_1  , y_1 )  , m :  the slope

note 2 :

the slope is :   m = (y_2 - y_1)/(x_2 -x_1)  when given two points  :

A(x_1  , y_1 )  and  B(x_2  , y_2 )

in this exercice :  x_1 =0      y_1 =3            x_2 =1      y_2 =1

calculate now   m = (1 - 3)/(1 -0) =-2

an equation  in point-slope form is : y - y_1 = m(x - x_1)  

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5 0
3 years ago
A scientist was in a submarine below sea level, studying ocean life. Over the next ten minutes, she dropped 24.9 feet. How many
Harrizon [31]

The Depth of the Scientist before dropping is;  42.2 ft

<h3>How to calculate sea level elevation?</h3>

It is pertinent to note that sea level is usually considered zero level. Thus, one is either above the sea level (positive sign) or below the sea level.

Now, we are told that the scientist was already below the sea level before she dropped 24.9 ft.

Now, if after dropping 24.9 ft, she is now 66.7 ft below sea level, then it means that the depth she was at before dropping 24.9 ft is;

Depth before dropping 24.9 ft = 66.7 - 24.9

Depth before dropping = 42.2 ft

Read more about Sea level Elevation at; brainly.com/question/2092614

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8 0
1 year ago
Prove that ΔABC and ΔEDC are similar.
Lesechka [4]

Answer:

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Step-by-step explanation:

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Citrus2011 [14]
The answer the the question is A.
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3 years ago
Bertha buys electricity from a company that offers a choice of two tariffs. Both have a daily charge of $0.20 regardless of how
Alenkasestr [34]

Answer: D ( 17/20)

Step-by-step explanation:

The two choices are:

The ‘standard’ tariff charges = $0.10 per unit

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= 2.12

The proportion will be

1.8/2.12 = 17/20 ( approximately)

6 0
3 years ago
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