All categories

4 years ago

For f(x)=5x−x2 , use the definition of a derivative to find f′(x)

1 answer:

4 0

$\bf f(x)=5x-x^2\qquad \qquad \lim\limits_{h\to 0}~\cfrac{f(x+h)-f(x)}{h} \\\\[-0.35em] ~\dotfill\\\\ \lim\limits_{h\to 0}~\cfrac{[5(x+h)-(x+h)^2]~~-~~[5x-x^2]}{h} \\\\\\ \lim\limits_{h\to 0}~\cfrac{[5x+5h-(x^2+2xh+h^2)]~~-~~5x+x^2}{h}$

$\bf \lim\limits_{h\to 0}~\cfrac{\begin{matrix} 5x \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}+5h~~\begin{matrix} -x^2 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}-2xh-h^2~~-~~\begin{matrix} 5x +x^2\\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}}{h}\implies \lim\limits_{h\to 0}~\cfrac{5h-2xh-h^2}{h}$

$\bf \lim\limits_{h\to 0}~\cfrac{\begin{matrix} h \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix} ~~(5-2x-h)}{\begin{matrix} h \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix} }\implies \lim\limits_{h\to 0}~5-2x-0\implies \lim\limits_{h\to 0}~5-2x$

You might be interested in

I will give you ALL of my 50 points if you did this

netineya [11]

If you send me the points I’ll do it in the comments

3 0

3 years ago

Life Expectancies In a study of the life expectancy of people in a certain geographic region, the mean age at death was years an

Sphinxa [80]

Answer:

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

We have:

Mean $\mu$ , standard deviation $\sigma$ .

Sample of size n:

This means that the z-score is now, by the Central Limit Theorem:

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

Find the probability that the mean life expectancy will be less than years.

8 0

3 years ago

at noon joice drove to the lake at 30 mi. per hour, but she made a long walk back at 4 mi. per hour. how long did she walk ifshe

Kryger [21]

Distance = 30 mph * time
distance = 4 mph * time

distance = 30 mph * t
distance = 4 mph * (17-t)

Since distance is equal then
30 mph * t = 4 mph * (17-t)

30t = -4t + 68

34t = 68

t = 2 hours

We see the return trip time is (17 -t ) which is 15 hours.
The beginning trip time is 2 hours.

Double Check
Beginning trip = 30 miles * 2 = 60 miles
Return trip = 4 miles * 15 = 60 miles.

3 0

3 years ago

Help me please thank you

harina [27]

I believe it would be 2 units to the right

and 4 units down

7 0

3 years ago

A black bear has a tail 190 mm long.How many cm is that?

GarryVolchara [31]

Answer:19

Step-by-step explanation:

Divide 190 by 10

7 0

4 years ago

Read 2 more answers