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3 years ago

What is a complex number ?

1 answer:

5 0

Answer:A complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x² = −1. Because no real number satisfies this equation, i is called an imaginary number.

Step-by-step explanation:

You might be interested in

Vic is standing on the ground at a point directly south of the base of the CN Tower and can see the top when looking at an angle

Sindrei [870]

The angle of elevation of 61° and 72° with the height of the tower being 553.3 m. gives Vic's distance from Dan as approximately 356 meters.

<h3>How can the distance between Vic and Dan be calculated?</h3>

Location of Vic relative to the tower = South

Vic's sight angle of elevation to the top of the tower = 61°

Dan's location with respect to the tower = West

Dan's angle of elevation in order to see the top of the tower = 72°

Height of the tower = 553.3m

$tan( \theta) = \frac{opposite}{adjacent}$

$tan( 61 ^{ \circ}) = \frac{553.3}{ Vic' s\: distance \: to \: tower}$

$distance = \frac{553.3}{tan ( {61}^{ \circ} )} = 306.7$

Vic's distance from the tower ≈ 306.7 m

Similarly, we have;

$Dan's distance = \frac{553.3}{tan ( {72}^{ \circ} )} = 179.8$

Dan's distance from the tower ≈ 179.8 m

Given that Vic and Dan are at right angles relative to the tower (Vic is on the south of the tower while Dan is at the west), by Pythagorean theorem, the distance between Vic and Dan <em>d </em>is found as follows;

d = √(306.7² + 179.8²) ≈ 356

Therefore;

Vic is approximately 356 meters from Dan

Learn more about Pythagorean theorem here:

brainly.com/question/343682

#SPJ1

4 0

1 year ago

If Upper X overbar equals 62, Upper S equals 8, and n equals 36, and assuming that the population is normally distributed, c

marishachu [46]

Answer:

The 99% confidence interval would be given by (58.373;65.627)

We are 99% confident that the true mean for the variable of interest is between 58.373 and 65.627.

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".

$\bar X=62$ represent the sample mean

$\mu$ population mean (variable of interest)

s=8 represent the sample standard deviation

n=36 represent the sample size

Part a: Confidence interval

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

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

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=36-1=35$

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,35)".And we see that $t_{\alpha/2}=2.72$

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

$62-2.72\frac{8}{\sqrt{36}}=58.373$

$62+2.72\frac{8}{\sqrt{36}}=65.627$

So on this case the 99% confidence interval would be given by (58.373;65.627)

We are 99% confident that the true mean for the variable of interest is between 58.373 and 65.627.

3 0

3 years ago

What is the percentage between 1192.64 and 819.73

Licemer1 [7]

1192.64-819.73 is 372.91

so... if we take 1192.64 to be the 100%, how much is 372.91 in percentage then?

$\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
1192.64&100\\
372.91&p
\end{array}\implies \cfrac{1192.64}{372.91}=\cfrac{100}{p}\implies p=\cfrac{372.91\cdot 100}{1192.64}$

3 0

2 years ago

sara buys a sweater at a department store the sweater costs $30 the store is having a 25% off sale on everything in the store. e

tatuchka [14]

Answer:

$7.50

Step-by-step explanation:

Sara buys a sweater that costs $30

The store is having a 25% off sale.

To figure out what 25% is you do 25/100, which will give you 0.25,

Multiply 0.25 by $30

You should get $7.50.