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2 years ago

Prove the polynomial identity.

Mathematics

1 answer:

Kaylis [27]2 years ago

5 0

Answer:

Proven

Step-by-step explanation:

We prove the polynomial with factorization. We must first simplify the expression before we can factorize:

$(4\cdot{x^2}-2)\cdot{(4\cdot{x^2}-2)}-16\cdot{x^4}$

$16\cdot{x^4}-8\cdot{x^2}-8\cdot{x^2}+4-16\cdot{x^4}$

$4-16\cdot{x^2}$

4 is the common number and we can take it out of the expression:

$4\cdot{(1-4\cdot{x^2})}$

We can factorize further with the x term being zero. For this to be true we must have -2x and 2x to cancel out and therefore the expression is proven:

$4\cdot{(1-2\cdot{x})}\cdot{(1+2\cdot{x})}$

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It is known that the life of a particular auto transmission follows a normal distribution with mean 72,000 miles and standard de

scoray [572]

Answer:

a) $P(X$

$P(z$

b) $P(X>65000)=P(\frac{X-\mu}{\sigma}>\frac{65000-\mu}{\sigma})=P(Z>\frac{65000-72000}{12000})=P(z>-0.583)$

$P(z>-0.583)=1-P(Z$

c) $P(X>100000)=P(\frac{X-\mu}{\sigma}>\frac{100000-\mu}{\sigma})=P(Z>\frac{100000-72000}{12000})=P(z>2.33)$

$P(z>2.33)=1-P(Z$

Sicne this probability just represent 1% of the data we can consider this value as unusual.

d) $z=1.28$

And if we solve for a we got

$a=72000 +1.28*12000=87360$

So the value of height that separates the bottom 90% of data from the top 10% is 87360.

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the life of a particular auto transmission of a population, and for this case we know the distribution for X is given by:

$X \sim N(72000,12000)$

Where $\mu=72000$ and $\sigma=12000$

We are interested on this probability

$P(X$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X$

And we can find this probability using excel or the normal standard table and we got:

$P(z$

Part b

$P(X>65000)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X>65000)=P(\frac{X-\mu}{\sigma}>\frac{65000-\mu}{\sigma})=P(Z>\frac{65000-72000}{12000})=P(z>-0.583)$

And we can find this probability using the complement rule and excel or the normal standard table and we got:

$P(z>-0.583)=1-P(Z$

Part c

$P(X>100000)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X>100000)=P(\frac{X-\mu}{\sigma}>\frac{100000-\mu}{\sigma})=P(Z>\frac{100000-72000}{12000})=P(z>2.33)$

And we can find this probability using the complement rule and excel or the normal standard table and we got:

$P(z>2.33)=1-P(Z$

Sicne this probability just represent 1% of the data we can consider this value as unusual.

Part d

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.1$ (a)

$P(X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.9 of the area on the left and 0.1 of the area on the right it's z=1.28. On this case P(Z<1.28)=0.9 and P(z>1.28)=0.1

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=1.28$

And if we solve for a we got

$a=72000 +1.28*12000=87360$

So the value of height that separates the bottom 90% of data from the top 10% is 87360.

5 0

3 years ago

a pitcher could hold two twelfths of a gallon of water. If Roger filled up nine pitchers, how much water would he have?

Ivenika [448]

2/12=1/6
(1/6)×9=9/6=1.5 gallons

5 0

3 years ago

Which of the following is a monomial?

Alex787 [66]

It is c2+c+6 .......

4 0

3 years ago

Read 2 more answers

) Jess has saved dimes ($ 0.10) and quarters ($ 0.25) in their piggy bank. Define the variables and write a

Mamont248 [21]

Answer:

Quarters = 10

Dimes = 15

Step-by-step explanation:

d = number of dimes, q = number of quarters

d + q = 25 is the equation for number of coins

0.1d + 0.25q = 4 is the equation for value of coins

First, solve for d in terms of q:

d + q = 25

d = 25 - q

Then substitute that into the other equation:

0.1(25 - q) + 0.25q = 4

2.5 - 0.1q + 0.25q = 4

0.15q = 1.5

q = 10

And back to d = 25 - q, d = 25 - 10 = 15

Check the math:

0.1(15) + 10(0.25) = 1.5 + 2.5 = 4

LMK if you have questions

4 0

2 years ago

A school holds classes from 8:00 A.M to 2:00 P.M. For what percent of 24-hour day does this school hold classes?

lesya [120]

Answer:

25%

Step-by-step explanation:

So first we need to find out how many hours the school has class. Its 4 hours from 8 to noon, then another 2 from noon to 2. This means the school has class 6 hours a day.

Now we need to figure out the percent. we need to have hours of school over total hours or 6/24

6/24

we can simplify this by dividing both sides by 6

(6/6)/(24/6)=1/4

1/4 is 25%

The school holds class for 25% of the day

5 0

3 years ago

Read 2 more answers