What is the exact value of cos (7pi/8)

What Is The Exact Value Of Cos (7pi/8)

Answers

Answer 1

Answer:

The bottom one ....see below

Step-by-step explanation:

Using reference angle of pi/8   and half angle trig identity:

cos ( angle/2) = -sqrt  (1 + cos (angle) /2)

cos ( pi/4  / 2) = - sqrt (1+ cos ( pi/4)/2)

  cos (pi/8)      = -    sqrt (1 + sqrt (2) / 2)

                 = - sqrt (1 + sqrt 2) / sqrt 2     rationalize the denominator

                    = - sqrt ( sqrt 2 + 2) / 2

re arrange to

          - sqrt ( 2 + sqrt2)  / 2        the fourth answer  


Related Questions

6E and 7 with full explanation

Answers

Answer:

See below ~

Step-by-step explanation:

Question 6(e) :

⇒ x² ≤ 16

Take square root on each side :

⇒ √x² ≤ √16

⇒ x ≤ 4 and x ≥ -4

-4 ≤ x ≤ 4

Part 6e

⇒ x² ≤ 16

Apply the absolute rule if x² < a then -√a < x < √a

⇒ -√16 ≤ x ≤ +√16

⇒ -4 ≤ x ≤ 4

Part 7

First of all, The student should have subtracted both sides by 4

What he should have done:

[tex]\rightarrow \sf \dfrac{3}{x-2} > 4[/tex]

[tex]\rightarrow \sf \dfrac{3}{x-2} -4 > 4 -4[/tex]

[tex]\rightarrow \sf \dfrac{3}{x-2} -\dfrac{4(x-2)}{x-2} > 0[/tex]

[tex]\rightarrow \sf \dfrac{3-4(x-2)}{x-2}} > 0[/tex]

[tex]\rightarrow \sf \dfrac{3-4x+8}{x-2}} > 0[/tex]

[tex]\rightarrow \sf \dfrac{-4x+11}{x-2}} > 0[/tex]

[tex]\sf \large \boxed{\sf {\left \{ {{-4x+11 = 0} \atop {x-2 = 0}} \right. }}[/tex]

⇒ -4x + 11 = 0, x - 2 = 0

⇒ -4x = -11, x = 2

⇒ x = 11/4 , x = 2

Solution satisfying the inequality:

2 < x < 11/4

By using a problem-solution structure, the author is able to show readers how people are hurting the planet. The structure also shows how we can change and what we can do to help solve the problems we have caused. It inspires people to take action

Answers

Answer:

One of the problems humans have made is a large amount of pollution.

And so some of the ways we can fix this is;

1- Using electric cars.

2- Using reusable packaging.

3- For the final one you could use stuff that easily and quickly to break down naturally materials.

Step-by-step explanation:

In a class of 28 students, 21 have a cat and 9 have a dog. There are 7 students who
have a cat and a dog. What is the probability that a student has a dog given that they
do not have a cat?

Answers

The probability that a student has a dog given that they do not have a cat is 1/14.

What is the probability?

Probability refers to a possibility that deals with the occurrence of random events.

The probability of all the events occurring need to be 1.

P(E) = Number of favorable outcomes / total number of outcomes

In a class of 28 students, 21 have a cat and 9 have a dog.

There are 7 students who have a cat and a dog.

The probability that a student has a dog given that they do not have a cat

= 2/ 28

= 1/14

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Which expression is equivalent to – 2 log2 x + 4 log2 y + 4 log2 z? log base 2 of the quantity x squared y to the fourth all divided by z to the fourth log base 2 of the quantity y to the fourth z to the fourth all divided by x squared log base 2 of the quantity y times z to the fourth all divided by x squared log base 2 of the quantity yz divided by x end quantity raised to the sixth

Answers

The expression equivalent to -2log₂x + 4log₂y + 4log₂z is log₂(yz)⁴/x².

To answer the question, we need to know the laws of logarithm

Laws of logarithmpower law - nlogₐx = logₐxⁿaddition law - logₐx + logₐy = logₐxy

Since we want to find the expression equivalent to -2log₂x + 4log₂y + 4log₂z, we simplify using these laws, we have

-2log₂x + 4log₂y + 4log₂z = log₂x⁻² + log₂y⁴ + log₂z⁴ (appying the power law)

= log₂x⁻²y⁴z⁴ (applying the multiplication law)

= log₂y⁴z⁴/x²

= log₂(yz)⁴/x²

So, the expression equivalent to -2log₂x + 4log₂y + 4log₂z is log₂(yz)⁴/x².

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Answer:

C.log_2(yz^4/x^2)

Step-by-step explanation:

I took the Algebra exam

HELP WITH THE RIGHT ASNWER FOR BRAINLIEST!!!!

Graph the line with slope 3 passing through the point (2,1).

Answers

Use the rough graph for answering your question

From the set {1, 2, 3, 4}, use substitution to determine which value of x makes the equation true. 4x = 8

Answers

answer is 2
Substitute each number into equation
4x = 8
4 (1) = 8. No
4 (2) = 8. Yes
4 (3) = 8. No
4 (4) = 8. No

A cylinder has a base radius of 9 feet and a height of 4 feet. What is its volume in
cubic feet, to the nearest tenths place?

Answers

The volume of the cylinder will be equal to 1017.87 cubic feet.

What is volume?

Volume is defined as the space occupied by any object in the three-Dimensions. For the cylinder, the volume will be calculated by radius and the height of the cylinder.


Given that:-

A cylinder has a base radius of 9 feet and a height of 4 feet.

The volume of the cylinder will be calculated by using the formulas below:-

V = πr²h

V = π ( 9 )² 4

V = 1017.87 cubic feet.

Therefore the volume of the cylinder will be equal to 1017.87 cubic feet.

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What percent of the first 20 natural numbers are prime one-digit numbers?

Answers

Answer:

5%

Step-by-step explanation:

The first 20 single digit first numbers are 2,3,5 and 7. Thus they are four.

So next we calculate the percentage:

⇒ 4  ×  100% = 1  × 100%  =  5%

   20                20

The table lists the test scores William and Andre received on five math assessments.

William’s Scores Andre’s Scores
89
90
97
74
78
73
81
87
91
82
Which statement best describes the difference of the mean of the two data sets?

Answers

statement best describes the difference of the mean of the two data sets 2.8 is about 1.5 times the mean absolute deviation of either set.

What is mean?

Mean is the average of the given numbers and is calculated by dividing the sum of given numbers by the total number of numbers.

The mean of William's set.

To find the mean, add all of the data points together and divide by the number of data points:

=89+90+97+74+78/5

=85.6

Now, mean absolute deviation,

=|89-85.6|+|90-85.6|+|97-85.6|+|74-85.6|+|78-85.6|/5

= 3.4+4.4+11.4+11.6+7.6/5

=7.68.

The mean of Andre's set.

To find the mean, add all of the data points together and divide by the number of data points:

=73+81+87+91+82/5

=82.8

Now, mean absolute deviation,

=|73-82.8|+|81-82.8|+|87-82.8|+|91-82.8|+|82-82.8|/5

=9.8+1.8+4.2+8.2+0.8/5

= 4.96.

Hence, the difference between the means of the two sets is

85.6-82.8=2.8.

2.8 is about 1.5 times the mean absolute deviation of either set.

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Answer:

Step-by-step explanation:

nothing im just as lost as everyone else

Sheila counted 9 blue jays and 21 sparrows at the bird feeder. What was the ratio of blue jays to sparrows?

Answers

Answer:

9/21

= 1/7

Step-by-step explanation:

ratio means the comparison of two things

A tower, 50 feet high, is secured with a guy wire anchored 8
feet from the base of the tower. What angle will the guy wire
make with the ground?

Answers

The tangent of an angle is the ratio of perpendicular to the base. The angle will the guy wire makes with the ground will be 80.91°.

What is trigonometry?

The connection between the lengths and angles of a triangular shape is the subject of trigonometry.

A tower, 50 feet high, is secured with a guy wire anchored 8 feet from the base of the tower.

The angle will the guy wire makes with the ground will be given by the tangent.

The tangent of an angle is the ratio of perpendicular to the base.

Then we have

tan θ = 50/8

tan θ = 6.25

     θ = tan ⁻¹ (6.25)

     θ = 80.9097

     θ ≅ 80.91°

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this is probability can someone please give me an answer

Answers

Answer:

The experimental probability is 4%

Step-by-step explanation:

50pts PLEASE HURRY UP I WILL GIVE BRAINLEST SHOW ALL OF YOUR WORK ANSWER ALL THE QUESTIONS

Use the spinner to answer the practice problems below:

Alice spins the spinner 2 times

What is the probability that the spinner stops on A and then B. or on B and then A?

Maria will spin the arrow on the spinner 2 times.

What is the probability that the arrow will stop on the same letter twice?​

Answers

Answer:

In two spins, there are 9 possible outcomes:  AA, AB, AC, BA, BB, BC, CA, CB, CCIf we assume each of these is equally likely, then the probability of AB or BA is ...  2/9

Step-by-step explanation:

Use the functions a(x) = 7x + 10 and b(x) = 12x - 18 to complete the function operations listed below.
Part A: Find (a + b)(x). Show your work.
Part B: Find (a - b)(x). Show your work.
Part C: Find (a - b)(x). Show your work.
Part D: Find a[b(x)]. Show your work.

Answers

The value of the sum, difference and composite function a[b(x)] are 19x - 8, -5x + 28 and 84x - 136 respectively

Sum and difference of functions

Given the following functions a(x) = 7x + 10 and b(x) = 12x - 18

Take the sum

(a+b)(x) = a(x) + b(x)

(a+b)(x) = 7x + 10 + 12x - 18

(a+b)(x) = 19x- 8

Take the difference

(a-b)(x) = a(x) - b(x)

(a-b)(x) = 7x + 10 - 12x + 18

(a-b)(x) = -5x + 28

For the composite function a[b(x)].

a(12x- 18) = 7(12x-18) - 10

a[b(x)] = 84x - 126 - 10

a[b(x)] = 84x - 136

Hence the value of the sum, difference and composite function a[b(x)] are 19x - 8, -5x + 28 and 84x - 136 respectively

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You bought 3 pounds of strawberries and 1 pound of blueberries for $8.40 to make pies for the summer festival. Your friend helped and bought 2 pounds of strawberries and 2 pounds of blueberries for $10.08. How much did a pound of blueberries cost? Let the cost of each pound of strawberries =x and the cost of each pound of blueberries = y

Answers

Step-by-step explanation:

3x + y = 8.4

2x + 2y = 10.08

x + y = 5.04

y = 5.04 - x

we use this then in the first equation

3x + 5.04 - x = 8.4

2x = 3.36

x = 3.36/2 = $1.68

y = 5.04 - x = 5.04 - 1.68 = $3.36

blueberries cost $3.36 per pound.

Nayeli lights a 4\,\text{m}^24m 2 4, start text, m, end text, squared space with 121212 candles. Citlali lights a 10\,\text{m}^210m 2 10, start text, m, end text, squared space with 303030 of the same type of candles. Whose space is lit brighter? Choose 1 answer: help me im graded at this

Answers

Using proportions, it is found that both spaces have the same brightness, as both have 3 candles per m².

The correct question is as given below:-

Nayeli lights a 4 square meter space with 12 candles. Citlali lights a 10 square meter space with 30 of the same type of candles. Whose space is lit brighter? Choose 1 answer: help me im graded at this

What is a proportion?

A proportion is a fraction of a total amount, and the measures are related using a rule of three.

For Nayeli and Citlali, the rate of candles per m² is given by:

N = 12/4 = 3 candles per m².

C = 30/10 = 3 candles per m².

Hence both spaces have the same brightness, as both have 3 candles per m².

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Find the slope of a line parallel to the line that passes through (-4, -1) and (-1, 3)

Answers

Answer:

[tex] \boxed{\rm \: Slope(m)= \cfrac{4}{ 3} }[/tex]

OR

[tex] \boxed{\rm \: Slope(m) \approx \: 1.30} \rm \: (nearest \: tenth)[/tex]

Step-by-step explanation:

Given two coordinates:

(-4, -1) and (-1, 3)

To Find:

The slope of given two coordinates

Solution:

In this case,we'll need to use the slope's formula,to get the slope.

Here's the formula:

[tex] \rm \: Slope(m)= \: \cfrac{ y_2 -y_1 }{x_2 - x_1} [/tex]

Slope is usually denoted as m.

According to the question:

[tex] \rm (y_2 , y _1) = (3,-1)[/tex][tex]\rm (x_2 , x_1) = (-1,-4)[/tex]

Substitute them accordingly:

[tex] \rm \: Slope(m)= \cfrac{3 - ( - 1)}{ - 1 - ( - 4)} [/tex]

Simplify then, using a rule called PEMDAS.

[tex] \rm \: Slope(m)= \cfrac{3 + 1}{ - 1 +4 } [/tex]

[tex] \rm \: Slope(m)= \cfrac{4}{ 3} [/tex]

[tex] \rm \: Slope(m) \approx \: 1.30[/tex]

Hence, we can conclude that:

The slope of a line parallel to the line that passes through (-4, -1) and (-1, 3) is 4/3 in exact form and 1.30 in approximate decimal form.

Hi student, let me help you out! :)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

We are asked to find the slope of a line parallel to the line that passes through

[tex]\star~\mathrm{(-4,-1)}\star[/tex]

[tex]\star~\mathrm{(-1,3)}[/tex]

[tex]\triangle~\fbox{\bf{KEY:}}[/tex]

The slope formula will help us out! :)

Here's the formula:

[tex]\star\boxed{\mathrm{\cfrac{y2-y1}{x2-x1}}}[/tex]

y2 and y1 are y-coordinates

x2 and x1 are x-coordinates

Substitute the given values:

[tex]\star\mathrm{\cfrac{3-(-1)}{-1-(-4)}}[/tex]

Simplify!

[tex]\star\mathrm{\cfrac{3+1}{-1+4}}[/tex]

Simplify more!

[tex]\star\mathrm{\cfrac{4}{3}}[/tex]

Now, what is the slope of the line parallel to this one?

Well, parallel lines have the same slope.

[tex]\star \ \mathrm{The \ slope \ of \ the \ line \ parallel \ to \ this \ one \ is \ \cfrac{4}{3}}.[/tex]

Hope it helps you out! :D

Ask in comments if any queries arise.

#StudyWithBrainly

~Just a smiley person helping fellow students :)

If f(n) = 2n^2 + 2 and g(n) = n + 1, what is (f -g)(n) when n = -1?

Answers

the easiest way is to first subtract them first and then replace n with -1:
2n^2+2-n-1 => 2n^2-n+1
now we replace n with -1
2(-1)^2-(-1)+1 => 2+2=4
"4" is teh final answer

Activity 2 :Collect the information on any one of the famous Mathematician :a) b) Bhaskara c) Shri Niwasan Ramanujan Aryabhatta please

Answers

Answer:

Bhāskara was a 7th-century mathematician and astronomer, who was the first to write numbers in the Hindu decimal system with a circle for the zero, and who gave a unique and remarkable rational approximation of the sine function in his commentary on Aryabhata's work. 

Aryabhatta is the father of Indian mathematics. He was a great mathematician and astronomer of ancient India. His major work is known as Aryabhatiya. It consists of spherical trigonometry, quadratic equations, algebra, plane trigonometry, sums of power series, arithmetic.

Step-by-step explanation:

hope it helps you and give brainliest

i needs help with it please ​

Answers

The triangle are similar because they satisfy the AAA postulate : Triangle ABC ~ Triangle PQR ( AAA similarity postulate )

Meaning of congruent triangles

A triangle can be defined as a plain shape that has three sides and three angles.

Congruent triangles are triangles that satisfy one or more congruence postulates or laws. The triangles could either be similar based on their angles or sides or angles and side being similar.

In conclusion, The triangle are similar because they satisfy the AAA postulate : Triangle ABC ~ Triangle PQR ( AAA similarity postulate )

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Write the converse of the statement
below.
If it is 9 a.m., then I am awake.

Answers

Answer:

if I am awake then it is 9 am.

Step-by-step explanation:

if p then q the converse is if q then p.

CAN SOMEONE HELP ME PLEASE? I’LL GIVE YOU FREE EASY POINTS IF YOU GIVE ME THE RIGHT ANSWER.. NO WRONG ANSWERS PLS!!

Answers

see the attachment..........

Work out the value of y in the equation
below.
бу
6y = 44 - 5у

Answers

Answer: Y = 6  1/2

Step-by-step explanation: Let's begin,

step 1) Isolate the variable by dividing each side by factors that don't contain the variable.

Then, Exact Form:

y = 13/2

Decimal Form:

y = 6.5

Mixed Number Form:

y = 6  1/2

need help would be apperacited .​

Answers

A function on a graph to figure it out you can do the line test where you draw a line through the graph and if the line touches two points its not a function. With this in mind bottom right is for sure one and the top left looks like one but i cant really tell...

Step-by-step explanation:

Okay I just got here I got a new car and I got my truck and I got my bike and I’m going to park now so I’m going to go buy one then I’ll stop bye bye buddy bye then I will see if he gets me too buddy I

Decagon, a=22 m, s=14.3 m

Answers

The area of the decagon is 1573.39 square meters

How to determine the area of the decagon?

The given parameters are:

Side length, s = 14.3 mApothem, a = 22 m

The area of a decagon is calculated using:

[tex]A = \frac 52s^2\sqrt{5 + 2\sqrt 5[/tex]

Substitute 14.3 for s

[tex]A = \frac 52 * 14.3^2\sqrt{5 + 2\sqrt 5[/tex]

Evaluate the exponent

[tex]A = \frac 52 * 204.49\sqrt{5 + 2\sqrt 5[/tex]

Evaluate the product and the roots

A = 1573.39

Hence, the area of the decagon is 1573.39 square meters

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What is the value of x???

Answers

The given polygon isa pentagon and the sum of its exterior angle is  360°. The value of x from the given polygon is 8

Sum of the exterior angle of a polygon

The given polygon isa pentagon and the sum of its exterior angle is  360°.

Take the sum of the angles and equate to  360° as shown;

77 + 66 + 62+ 59 + 12x =  360°

264 + 12x = 360

12x = 96

x = 8

Hence the value of x from the given polygon is 8

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Two dice are rolled. Event A is that the sum of the numbers is 7 or 11. Event B is that the sum of the numbers is 11 or 12. Find the probability of Event A or B(A union B)

Answers

Answer:

the probability is %25 percent :P

Step-by-step explanation:

-6 3/5 - (-7 4/15) + 2 1/5​

Answers

The answer to your question would be 43/15 or 2.866 and ongoing.

What is the value of x? 2 3 6 7

Answers

Answer:

6

Step-by-step explanation:

Answer:

2 or A

Step-by-step explanation:

Correct on edge22

ch of these is the absolute value parent function?
A. f(x) = x
B. f(x) = x^2
C. f(x) = |x|
D. f(x) = 2^x

Answers

Answer:

[tex] \text{C.} \: f(x) \: = \: |x| [/tex]

Step-by-step explanation:

To identify the absolute value of a number, it will always be represented between two sticks.

MissSpanish
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Read the question carefully and select the best answer. Which inference can be best made about the speakers father? Answer choices for the above question A. He is wise. B. He is educated. C. He is stern. D. He is disagreeable. Combine like terms to create an equivalent expression.Enter any coefficients as simplified proper or improper fractions or integers.-\dfrac65-\dfrac23v+\dfrac{4}{15}+\dfrac13v 56 32 v+ 154 + 31 vFrom khan academy Hanson Aquatics manufactures navigational equipment. As a new Hanson employee, Lyndon Kiely was told that even if he decides not to join the union that represents the company's employees, he must pay the dues. Hanson has a(n) _____ shop. What are the zeros of the function f(x) = x4 4x2 5? Californians who want to go to school beyond high school may choose to pursue their [_____________________] at one of the states many colleges or [_____________________________]. Other students may instead decide to attend a [_________________________], which teaches technical skills required for a specific type of job, such as auto repair or video game design. What are two obstacles to progress in developing nations. In circle P, diameter QS measures 20 centimeters.Circle P is shown. Line segment Q S is a diameter. Line segment R P is a radius. Angle R P S is 123 degrees.What is the approximate length of arc QR? Round to the nearest tenth of a centimeter.9.9 centimeters19.9 centimeters21.5 centimeters43.0 centimeter En el tiempo de los apostoles todos eran muy barbaros. Express your answer in simplest a+ bi form. (8+5i)(3+2i)-(4+i)(4-i) how many solutions does 10x - 10= -10x + 10 What was the first state to officially recognize memorial day?. Which of the following terms might be used by a company for product differentiation?new and improved50% more than the leading competitorthe lowest priceAll of the choices are correct.Lmk! After the stranger leaves, what does Elisa do?A. Cries and refuses to go into town with HenryB. Chases after the stranger and begs him to take her to San DiegoC. Makes plans to open her own flower business ( 12y + 2x) + 4y simplify the expression Land AreaCityChicago(in square miles)227.635468.670Population(in 2011)2,707,120Los Angeles3,819,702To the nearest tenth, by how many people per square mile is the population density of Chicago greater than the population density ofLos Angeles? In order to go on the field trip, you must accrue 75 positive behavior points. you found out that you have 45% of the points necessary to go. how many points do you have? use the variable, p, for your equation. what is the equation? In British Pharmacopoeia (BP) assay for content of active ingredient, 20 tablets(each stated to contain 50 mg of active ingredient) of total weight 6.5142g werepowdered. A sample of the powdered tablets of weight 0.3460g was extractedwith 0.1M NaOH, the extract filtered, and the filtrate made up to 100 cm3 with0.1 M NaOH. A dilution ( 1 in 100 ) with 0.1M NaOH gave an absorbency valueof 0.345 at 256 nm using 1 cm cells. Given that the A (1%, 1cm) is 658 at 257 nmin 0.1M NaOH. Calculate the percentage of the stated amount of activeingredient per tablet A study was conducted about the number of miles that a sample of automobiles in New York City drive within a year. The sample was taken in front of an apartment complex and included 20 taxicab drivers and 40 of the buildings residents. Which is a reasonable explanation for the large gap in the histogram? What is the heat abosorbed by 47.5g of silver (Ag) when the temperature rises by 10.0C? How many children are working around the world today, according to the ilo? a. 215,000 b. 2.15 million c. 21.5 million d. 215 million