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2 years ago

Which of the following is the difference of two squares

Mathematics

1 answer:

Roman55 [17]2 years ago

7 0

Answer:

2nd option

Step-by-step explanation:

A difference of squares has the general form

a² - b²

where the terms on either side of the subtraction ( the difference ) are both perfect squares.

The only one fitting this description is

16a² - 4y²

= (4a)² - (2y)² ← difference of squares

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What is the area of a circle with a radius of 2.1cm? Use 3.14 for π.

saul85 [17]

Answer: I got's you lol

A≈13.85cm²

And the radius is 2.1

Step-by-step explanation:

Hope this helps let me know :)

3 0

3 years ago

Read 2 more answers

Researchers are interested if a school breakfast program leads to taller children. Assume that the population of all 5 year-old

DedPeter [7]

Answer:

$39-1.96\frac{1}{\sqrt{25}}=38.608$

$39+1.96\frac{1}{\sqrt{25}}=39.392$

So on this case the 95% confidence interval would be given by (38.608;39.392)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

$\bar X=39$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=1$ represent the population standard deviation

n=25 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

The margin of error is given by:

$ME= z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

And replacing we got:

$ME= 1.96 *\frac{1}{\sqrt{25}}= 0.392$

Now we have everything in order to replace into formula (1):

$39-1.96\frac{1}{\sqrt{25}}=38.608$

$39+1.96\frac{1}{\sqrt{25}}=39.392$

So on this case the 95% confidence interval would be given by (38.608;39.392)

7 0

3 years ago

Which is the better buy a 3 pound ham for $5.70 or 5 pounds for $8.75

tekilochka [14]

Answer:

The larger ham is the better buy.

Step-by-step explanation:

In order to determine the better buy, divide both of the prices by their weight to get the price per pound of ham.

5.70/3 = 1.90 per lb

8.75/5 = 1.75 per lb

Therefore the 5 pound of ham is a better buy.

7 0

3 years ago

Read 2 more answers

Solve for x: 7x + 15 = 38

oksano4ka [1.4K]

All you do is move all the terms that don't contain " x " to the right side and solve.

x = $\frac{23}{7}$

Hope that helps, Good luck! (:

8 0

3 years ago

Read 2 more answers

Suppose that p is the probability that a randomly selected person is left handed. The value (1-p) is the probability that the pe

solmaris [256]

Answer:

a) 1/2

b) 250

Step-by-step explanation:

The start of the question doesn't matter entirely, although is interesting to read. What we are trying to do is find the value for $p$ such that $1000p(1-p)$ is maximized. Once we have that $p$ , we can easily find the answer to part b.

Finding the value that maximizes $1000p(1-p)$ is the same as finding the value that maximizes $p(1-p)$ , just on a smaller scale. So, we really want to maximize $p(1-p)$ . To do this, we will do a trick called completing the square.

$p(1-p)=p-p^2=-p^2+p=-(p^2-p)=-(p^2-p+1/4)-(-1/4)=-(p-1/2)^2+1/4$ .

Because there is a negative sign in front of the big squared term, combined with the fact that a square is always positive, means we need to find the value of $p$ such that the inner part of the square term is equal to $0$ .

$p-1/2=0\\p=1/2$ .

So, the answer to part a is $\boxed{1/2}$ .

We can then plug $1/2$ into the equation for p to find the answer to part b.

$1000(1/2)(1-1/2)=1000(1/2)(1/2)=1000*1/4=250$ .

So, the answer to part b is $\boxed{250}$ .

And we're done!

3 0

2 years ago