For i^2 =-1, (3-i)^2 = ? A. 8 B. 10 C. 8-6i D. 8 + 6i E. 10-6i

please help. answer is 62.1m(squared) and the objects are composite! please show the work, no matter what i do i cant seem to ge

yuradex [85]

Answer:

$SA=62.1\ m^2$

Step-by-step explanation:

step 1

Find the surface area of the smaller rectangular prism

$SA=2B+Ph$

where

B is the area of the base

P is the perimeter of the base

h is the height of the prism

$SA=2[(2.5)(1.5)]+2(2.5+1.5)(1.5)$

$SA=7.5+12=19.5\ m^2$

step 2

Find the surface area of the cube

$SA=6s^2$

where

s is the length side of the cube

$SA=6(2.5^2)=37.5\ m^2$

step 3

Find the lateral area of the cylinder

$LA=\pi DL$

where

D is the diameter of the base

L is the length of cylinder

$LA=(3.14)(0.5)(3.5)=5.495\ m^2$

step 4

Find the area of the base of cylinder

$A=\pi r^{2}$

we have

$r=0.5/2=0.25\ m$ ----> the radius is half the diameter

$A=(3.14)(0.25)^{2}=0.19625\ m^2$

step 5

Find the surface are of the composite figure

we know that

The surface area of the composite figure is equal to the surface area of the smaller rectangular prism plus the lateral area of the cylinder, plus the surface area of the cube, minus the area of the two bases of cylinder

so

$SA=19.5+5.495+37.5-2(0.19625)=62.1\ m^2$

5 0

2 years ago

My brother wants to estimate the proportion of Canadians who own their house.What sample size should be obtained if he wants the

AVprozaik [17]

Answer:

a) $n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

b) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

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".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Part a

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

Part b

For this case since we don't have a prior estimate we can use $\hat p =0.5$

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

8 0

2 years ago

90 • 4 – 14 ÷ 2 + 102 ÷ 5 • 2

sveta [45]

90*4-14/2+102/5*2

360-7+40,8

393,8

8 0

2 years ago

Read 2 more answers

The product of two numbers is 20. If one number is 5/7 what is the other number

Nostrana [21]

28. 5/7(x)=20

X=28

Hope this helps! :)

5 0

2 years ago

I need help with #1 10 points

Vikentia [17]

Answer:

No it is not proportional

Step-by-step explanation:

You cant multiply each of the inputs by a constant number to get the output.

There is only 2 of them that you can, but the other 2 no. And you want he whole table so you need all of the inputs not just some. So no, its not proportional.

Hope this helped!

4 0

3 years ago