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3 years ago

Write the sum using summation notation, assuming the suggested pattern continues. 2 - 8 + 32 - 128 + ...

1 answer:

4 0

This is a geometric series with first term 2 and common ratio -4. The general term of such a series (an) in terms of the first term (a1) and common rato (r) is written as
an = a1*r^(n-1)

The sum is the sum of such terms.
$sum=\sum\limits_{n=1}^{\infty}{2(-4)^{(n-1)}}$

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Give at least four different symbols that have been used to represent specific statistical measures. Describe what measure each

natta225 [31]

Answer:

Variance 0²

standard deviation 0×

mean α

median x-bar

Step-by-step explanation:

these are the four different symbols that have been used to represent specific statistical measures like for example, mean which is used to calculate the average value of a sample or population. Variance is the what is expected from the squared standard deviation of a random variable from is average vale/ mean. Median is the value that lies in the middle in a random sample and lastly the standard deviation is the square root of the variance and it measures how the values of sample are spread or how far are they from the mean. these are also commonly use in excel a lot to calculate and evaluate data.

6 0

2 years ago

You are situated 300 feet from the base of Tower Glitz Plaza watching an external elevator descend down the side of the building

nordsb [41]

Answer:

18.66 ft/s

Step-by-step explanation:

The distance between you and the elevator is given by:

$h=\sqrt{x^2+y^2}$

The rate of change for the distance between you and the elevator is given by:

$\frac{dh}{dt}=\frac{dh}{dy}*\frac{dy}{dt}$

$-16=\frac{dh}{dy}*\frac{dy}{dt}$

$\frac{dh}{dy}=\frac{d}{dy} (\sqrt{x^2+y^2})\\$

Applying the chain rule:

$u=x^2+y^2\\\frac{dh}{dy}=\frac{d\sqrt u}{du} *\frac{du}{dy}\\\frac{dh}{dy}=\frac{1}{2\sqrt u} *2y\\\frac{dh}{dy}=\frac{y}{\sqrt {(x^2+y^2)}}$

Therefore, at x=300 and y = 500, dy/dt is:

$-16=\frac{y}{\sqrt {(x^2+y^2)}}*\frac{dy}{dt}\\-16=\frac{500}{\sqrt {(300^2+500^2)}}*\frac{dy}{dt}\\\frac{dy}{dt}=-18.66\ ft/s$

The elevator is descending at 18.66 ft/s.

7 0

2 years ago

A worn, poorly set-up machine is observed to produce components whose length X follows a normal distribution with mean 14 centim

Akimi4 [234]

Answer:

74.86% probability that a component is at least 12 centimeters long.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 14$