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3 years ago

13

Complete the recursive formula of the geometric sequence 7, -14, 28, -56, ....

1 answer:

Dafna11 [192]3 years ago

4 0

Answer:

$a_{n}$ = - 2 $a_{n-1}$

Step-by-step explanation:

A geometric recursive formula has the form

$a_{n}$ = r $a_{n-1}$

where r is the common ratio

Here r = - 14 ÷ 7 = - 2, thus

$a_{n}$ = - 2 $a_{n-1}$ with a₁ = 7

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Maksim231197 [3]

Answer:

The sample standard deviation is 393.99

Step-by-step explanation:

The standard deviation of a sample can be calculated using the following formula:

$s=\sqrt[ ]{\frac{1}{N-1} \sum_{i=1}^{N}(x_{i}-{\displaystyle \textstyle {\bar {x}}}) ^{2} }$

Where:

$s=$ Sample standart deviation

$N=$ Number of observations in the sample

${\displaystyle \textstyle {\bar {x}}}=$ Mean value of the sample

and $\sum_{i=1}^{N}(x_{i}-{\displaystyle \textstyle {\bar {x}}}) ^{2} }$ simbolizes the addition of the square of the difference between each observation and the mean value of the sample.

Let's start calculating the mean value:

$\bar {x}=\frac{1}{N} \sum_{i=1}^{N}x_{i}$

$\bar {x}=\frac{1}{15}*(180+1600+90+140+50+260+400+90+380+110+10+60+20+340+80)$

$\bar {x}=\frac{1}{15}*(3810)$

$\bar {x}=254$

Now, let's calculate the summation:

$\sum_{i=1}^{N}(x_{i}-\bar {x}) ^{2} }=(180-254)^2+(1600-254)^2+(90-254)^2+...+(80-254)^2$

$\sum_{i=1}^{N}(x_{i}-\bar {x}) ^{2} }=2173160$

So, now we can calculate the standart deviation:

$s=\sqrt[ ]{\frac{1}{N-1} \sum_{i=1}^{N}(x_{i}-{\displaystyle \textstyle {\bar {x}}}) ^{2} }$

$s=\sqrt[ ]{\frac{1}{15-1}*(2173160)}$

$s=\sqrt[ ]{\frac{2173160}{14}}$

$s=393.99$

The sample standard deviation is 393.99

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4 years ago

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scoray [572]

Given:

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The value of x.

Solution:

<em>If two chords intersect each other inside a circle, the products of length their segments are equal.</em>

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