Please solve the following problem.

Express the complex number [tex]z = 8 \text{cis} \frac{2\pi}{3}[/tex] in rectangular form [tex]a+bi[/tex].

Answers

Answer 1

Answer:

- 4 + 4√3 i, where a = -4 & b = 4√3

Step-by-step explanation:

z = 8 cis(2π/3)

z = 8 [cos(2π/3) + i sin(2π/3) ]

z = 8 [cos(π - π/3) + i sin(π - π/3)]

z = 8 [ - cosπ/3 + i sin(π/3)]

z = 8[ - 1/2 + i √3/2 ]

z = - 4 + 4√3 i [in a + bi form]

Note that: cis x = cosx + i sinx

Answer 2

Answer:

[tex]a + bi = - 4 + 4 \sqrt{3} i[/tex]

Step-by-step explanation:

we are given [tex]\displaystyle cis(\dfrac{2\pi}{3})[/tex]

recall complex number trigonometric form:

[tex] \displaystyle \: r( \cos( \theta) + i \sin( \theta) )[/tex]

we are already given that [tex]\theta=\dfrac{2\pi}{3}[/tex]

recall complex number rectangular form

[tex] \displaystyle \: a + bi[/tex]

where [tex]\displaystyle a=r\cos(\theta)\: and\: b=r\sin(\theta)[/tex]

let's work with a:

substitute the value of [tex]\theta[/tex] and r

[tex] \displaystyle \: a = 8 \times \cos( \frac{2\pi}{ 3} ) [/tex]

recall unit circle

so [tex]\cos(\dfrac{2\pi}{3})[/tex] should be in Q:II

[tex] \displaystyle \: a = 8 \times - \frac{1}{2} [/tex]

simplify multiplication:

[tex] \displaystyle \: a = - 4[/tex]

let's work with b:

substitute the value of [tex]\theta[/tex] and r:

[tex] \displaystyle \: b = 8\sin( \frac{3\pi}{2} ) [/tex]

recall unit circle so [tex]\sin(\dfrac{3\pi}{2})[/tex] should be in Q:II

[tex] \displaystyle \: b = 8 \times \frac{ \sqrt{3} }{2} [/tex]

simplify:

[tex] \displaystyle \: b = 4 \sqrt{3} [/tex]

so

[tex] \displaystyle \: b i= 4 \sqrt{3} i[/tex]

hence,

[tex]a + bi = - 4 + 4 \sqrt{3} i[/tex]


Related Questions

Kennedy lives in the middle of the city. Her friend Zoe lives 8 miles to the west and her friend Shiloh lives 6 miles to the south. Approximately how far apart do Zoe and Shiloh live from each other?

Answers

Answer:

i would say about 16 miles.

Answer:

Step-by-step explanation:

Draw a picture. The lines between their houses forms a right triangle. Kennedy is at the 90°. The distance between Shiloh and Zoe is the hypotenuse of the triangle, so use the Pythagorean Theorem.

Distance² = 8² + 6² = 100

Distance = √100 = 10 miles

Plzzzz help me thxs !!!

Answers

Answer:

b) 2 (x - 4) = 6x

Step-by-step explanation:

equation:

⇒ 2 (x - 4) = 6x

use distributive property:

⇒ 2 (x - 4) = 6x

⇒ 2x - 8 = 6x

subtract x from both sides:

⇒ 2x - 2x - 8 = 6x - 2x

⇒ -8 = 4x

divide both sides by 4:

⇒ [tex]\frac{-8}{4} = \frac{4x}{4}[/tex]

⇒ -2 = x

to check, substitute -2 for x: answer should be the same

2 (x - 4) = 6x

2 (-2 - 4) = 6 x -2

-4 - 8 = -12

-12 = -12

Answer:

i got A and B.

Step-by-step explanation:

for a, subtract 6 from both sides and your new equation should be 2x=-4

the divide -4 by 2 which is -2

for b, you multiply 2 by each number in the parenthesis so your new equation should be 2x-8=6x. then subtract 2x from 6x and get 4x then divide -8 by 4 to get -2. im 100% sure abt A but i was a little confused on B good luck tho

plssss help im stuck and this is worth 20 percent

Answers

Answer:

Percentile 2020 Percent Change

18%           $4,480.43 30.8%

19%      $5,378.37 24.0%

20%   $6,368.35 24.3%

21%         $7,363.47 22.4%

Step-by-step explanation:

Please help me. I need help

Answers

I am pretty sure the answer would be -.02
Bc you would do 2-3.6/5- -3

PLEASE I NEED HELP CLICK ON THIS IMAGE

Answers

Answer:

14 and 15

Step-by-step explanation:

Help please someone

Answers

If I’m right I think it’s 2.90 so sorry if it’s wrong

4
Multiplying a number by and then dividing by is the same as doing what to the
number?
А
Dividing by 4
B
Multiplying by 2
С
Multiplying by 2
D
Dividing by 5
E
Multiplying by 5

Answers

d, let me know if you need explanationn <33333

Helppppp !!!!!!

During a 20 kilometer hike, Deana consumed 3 3/4 quarts of water.


What was Deana's average water consumption in quarts per kilometer?

Answers

Answer:

16.7

Step-by-step explanation:

The amount of water consumed is 334 quarts

The distance is 20km

Therefore the average water consumption can be calculated as follows

= 334/20

= 16.7

Hence the consumption rate is 16.7 quarts/km

What is the volume to the nearest thousandth? Does anyone know

Answers

The nearest volume to a thousand is I think 10x10x10x10

A line with a slope of 0 passes through the point (9,5). What is its equation in slope-intercept form?
Write your answer using integers, proper fractions, and improper fractions in simplest form.

Answers

Answer:

if the slope is 0, it is horizontal. and remember, m is the slope. (0)

Step-by-step explanation:

x is 9, y is 5.

slope intercept form is y=mx+b, so you plug in the numbers.

5= 0*9+5

or, 5=5

y =|x −3|+|x +2|−|x −5|, if x >5

Answers

Use photomath it’s faster and you get correct Answers!<3 have a good day

Answer: maybe -1

Step-by-step explanation:

NEED MAJOR HELP PLEASE

Answers

Answer:

∠ BDC = 30°

Step-by-step explanation:

The angle on the circle is half the measure of the central angle subtended by the arc BC

∠ BDC = [tex]\frac{1}{2}[/tex] × 60° = 30°

Please let me know asap

Answers

Answer:

100

Step-by-step explanation:

Hello There!

∠4 and ∠8 are corresponding angles

corresponding angles are congruent so if ∠4 = 100 then ∠8 also equals 100

2. Which of these is a combination problem?
How many different ways can a manager review 3 out of 5 employees if he reviews them in a specific order?
In how many different ways can Maria choose 5 roses from a bunch of 10 roses.
How many license plates can be formed with the digits 3, 2, 7, 0?
How many different ways can the letters in the word 'seven' be arranged?

Answers

THAT SHOULD BE THE ANSWER

Ambitious

268 answers

76.4K people helped

This is a fundamental counting principle problem and can be solved by multiplying the number of choices you have for each digit of the license plate.

For the first digit you can choose from the numbers 0,1,2...,9 or 10 choices.

Now the next 5 digits will all be letters all being different.. recall there are 26 letters in the alphabet.. for our second digit we have 26 choices, for our third digit we have 25 choices(because we already used one of the 26 letters and we can't repeat), for our fourth digit we have 24 choices.... and well I'm sure you are catching on by now...

Here is what the whole calculation looks like:

10(26)(25)(24)(23)(22) = 78,936,000

Step-by-step explanation:

Answer:

The answer should be the one with roses

Step-by-step explanation:

What is 2/5 + 3/10 + 1/2?​

Answers

the answer to your question is 1.2

answer: 2/5 + 3/10 + 1/2 = 1.2

The answer will be 1 and 1/5

I attached the work in the picture!

At Brett's Swimwear, 9 out of the 45 styles at the store are bikinis. What percentage of
swimsuit styles at the store are bikinis?

Answers

Answer:

20%

Step-by-step explanation:

What ordered pairs are the solutions of the system of equations shown in the graph below?

Answers

Answer:

(-3,1) and (-8,6)

Step-by-step explanation:

Hey gabymcarrillo!

The solution is always the place where the two lines intersect.

Our first answer: go 3 left on the x- axis, and then go 1 up on the y- axis. This results in (-3,1)

Our second answer: go 8 left on the x- axis, then go 6 up on the y- axis. This results in (-8,6)

Hope a helped, have a nice day!

          -Aadi x

Find the measure of an angle whose supplement measures two times its measure

Answers

Answer:

first angle = 60

second angle = 120

Step-by-step explanation:

Let the first angle  x

Let the second angle = 2x

x + 2x = 180        Supplementary angles = 180 degrees

3x = 180              Divide by 3

3x/3 = 180/3

x = 60

2x = 120

What is the value of the expression below when a = 5?
9a - 7 + 6

Answers

Answer:

44

Step-by-step explanation:

Hello There!

To solve this one all we have to do is plug in 5 for a

so

9(5)-7+6

9x4=45

45-7=38

38+6=44

so when a=5 the value of the expression is 44

w
What is the value of a?
4
5 units
C
Os units
O 6 units
O 7 units

Answers

Answer:

B.5 1/3

Step-by-step explanation:

got it right on edge

The value of a from the given triangle is [tex]5\frac{1}{3}[/tex] units. Therefore, option B is the correct answer.

What is the Pythagoras theorem?

The Pythagoras theorem which is also referred to as the Pythagorean theorem explains the relationship between the three sides of a right-angled triangle. According to the Pythagoras theorem, the square of the hypotenuse is equal to the sum of the squares of the other two sides of a triangle.

From the triangle we have WX=b, WZ=c, ZY=3, YX=a and WY=4.

By Pythagoras theorem,

c²=4²+3²

c²=16+9

c²=25

c=5 units

In triangle WXZ,

(3+a)²=5²+b² ----(i)

From the triangle WXY,

b²=4²+a² ------(ii)

From equation (i) and (ii), we get

(3+a)²=5²+4²+a²

9+6a+a²=41+a²

6a=32

a=32/6

a=[tex]5\frac{1}{3}[/tex] units

Therefore, option B is the correct answer.

To learn more about the Pythagoras theorem visit:

brainly.com/question/21926466.

#SPJ7

help me someone please​

Answers

Seventy two degrees

The table shows the prices for the same cereal, sold in different weights. Which size box is the best buy, in terms of price per ounce?

A. 9 oz
B.18 oz
C.28 oz
D.38 oz

Answers

Answer:

c

Step-by-step explanation:

ESPERO TE A YDUE :)

Ms. Cathy bought a package of pens. Out of every 10 ​, pens, 7 are black. If there are 20 pens in the​ pack, what fraction of the pens in the pack are​ black? What percent of the pens in the pack are​ black? What fraction of the Owens in the pack is​ black?

Answers

Answer:

Step-by-step explanation:

7/10 are black therefore 14/20 are black

18 is ______percent of 40

Answers

Answer:

18 is 45% of 40

Step-by-step explanation:

Tayler works at a bicycle shop. When he sells a bicycle, he earns 6% of the sale price as a commission. One day Tayler sold 1 bicycle for $125 and 2 bicycles for $75 each. What was the total amount of commission he earned?

Answers

Tayler made $16.5


$72x2=$150
$150+125=$275
6% of 275= $16.5

A petri dish is a small, shallow dish of thin glass or plastic, used especially for cultures in bacteriology. A 2-inch-radius petri dish, containing nutrients upon which bacteria can multiply, is smeared with a uniform suspension of bacteria. Subsequently, spots indicating colonies of bacteria appear. The distance of the center of the first spot to appear from the center of the petri dish is a variable with density curve y= x/2 for 0 < x <2 and y=0 otherwise.

a. Graph the density curve of this variable.
b. Show that the area under this density curve to the left of any number x between 0 and 2 equals x2/4.
c. What percentage of the time is the distance of the center of the first spot to appear from the center of the petri dish

1. at most 1 inch?
2. between 0.25 inch and 1.5 inches?
3. more than 0.75 inch?

Answers

Answer:

a) attached below

b) Area = 1/2 ( base ) (height )

        = 1/2 ( x ) ( x/2)

        = x^2 / 4

C) i)25%     ii) 54.69%      iii) 85.94%

Step-by-step explanation:

Given density curve y = x/2  for 0 < x < 2  and y = 0

a) Graph the density curve of this variable

attached below

b) show that the area under the density curve to the left of any number x between 0 and 2 equals x^2/4

base of triangle = x

height = x/2

Hence to show the area under the density curve is equal to x^2/4 we will calculate the area to the left

Area = 1/2 ( base ) (height )

        = 1/2 ( x ) ( x/2)

        = x^2 / 4

c) Determine the percentage of the time of the distance of the center of the first spot to appear from the center of the petri dish

i) At most 1 inch

(area to the left of 1 ) = 1^2 / 4

= 1/4 = 0.25 ≈  25%

ii)   between 0.25 inch and 1.5 inches?

( area between 0.25 and 1.5 ) = ( area to the left of 1.5 ) - ( Area to the left of 0.25 )

= (1.5^2 / 4 )- ( 0.25^2 / 4 )

= 0.5469 = 54.69%

iii) more than 0.75 inch

( Area to the right of 0.75 ) = 1 - (0.75^ / 4)

                                            = 0.8594 = 85.94 %

PLZ HELP I WILL MARK BRIANLIST Complete the table for 11, 15, and 19 days. Input your
answers. Then click done.
Number of Days
Total Number of
Trophies Won
80
slope
3
100 trophies
4 days
25 trophies
1 day
7
180
11
15
19
DONE

Answers

Answer:

275, 375, 475

Step-by-step explanation:

First, find the slope using the two pairs of values given.

Number of days = x

Total number of trophies = y

Using (3, 80) and (7, 180),

Slope = ∆y/∆x = (180 - 80)/(7 - 3) = 100/4 = 25

Slope/unit rate = 25 trophies per day

Multiply 25 by each given number of days to get each corresponding total number of trophies won.

Thus:

✔️Number of days = 11

Total number of trophies won = 11*25 = 275

✔️Number of days = 15

Total number of trophies won = 15*25 = 375

✔️Number of days = 19

Total number of trophies won = 19*25 = 475

Answer:

280

380

480

Step-by-step explanation:

If he gets 100 trophies every 4 days then you just add 100 to each column because in each one the days are increasing by 4

Your welcome ;)

The cost of 7 pounds of berries is $16.38, what is the cost per pound of
Berries?

Answers

Answer:

2.34

Hope that helps!

1. Which fraction is equivalent to a repeating decimal? A. 2/6 B. 34 C. 9/12 D. 78​

Answers

Answer:

Answer is A. 2/6

Step-by-step explanation:

Hope this helps! :)

Is 60.560 an irrational number or rational?

Answers

Answer: ratinal?

Step-by-step explanation:

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