Find the exact value using a half angle identity. Cos(-pi/8)

Answers

Answer 1

9514 1404 393

Answer:

  cos(-π/8) = (√(2+√2))/2

Step-by-step explanation:

The half-angle formula is ...

  \(\cos{\dfrac{\theta}{2}}=\pm\sqrt{\dfrac{1+\cos{\theta}}{2}}\)

Since cosine is an even function, cos(-π/8) = cos(π/8).

For θ/2 = π/8, θ = π/4 and cos(θ) = (√2)/2. Filling in the formula, we have ...

  \(\cos{(-\dfrac{\pi}{8})}=\cos{\dfrac{\pi}{8}}=\sqrt{\dfrac{1+\cos{\dfrac{\pi}{4}}}{2}}=\sqrt{\dfrac{1+\dfrac{\sqrt{2}}{2}}{2}}\\\\=\sqrt{\dfrac{2+\sqrt{2}}{4}}=\boxed{\dfrac{\sqrt{2+\sqrt{2}}}{2}}\)


Related Questions

help please :(
57%=

Answers

Answer:

57 centimeters = 57 × 0.39370078740175 = 22.4409448819 inches.

57 inches is 144.78 centimeters.

juwad picked 30 bags of apples on Monday and sold them at his fruit stand for $3.45 each. The following week he picked and sold 26 bags. Each bag Juwad picked holds 15 apples. How many apples did he pick in two weeks?

Answers

30 bags x 15 apples = 450 apples

26 bags x 15 apples = 390 apples

450 + 390 = 840 apples

Answer : 840 apples

What are the points of the image of the line in Q4 after the dilation?

What are the points of the image of the line in Q4 after the dilation?

Answers

Note that the coordinates of the point A' after rotating 90 degrees clockwise about the point (0,1) are (3, -4). (Option B)

How is this so ?

To rotate a point 90 degrees  clockwise about a given point,we can follow these steps -

Translate the coordinates   of the given point so that the center of rotation is at the origin.   In this case,we subtract the coordinates   of the center (0,1) from the coordinates of point A (5,4) to get (-5, 3).

Perform the rotation by swapping the x and y coordinates and changing the sign of the   new x coordinate. In this case,we  swap the x and y coordinates of (-5, 3)   to  get (3, -5).

Translate the coordinates back to their original position   by adding the coordinates of the center (0,1)  to the result from step 2. In   this case, we add (0,1) to (3, -5) to get (3, -4).

Therefore, the coordinates   of the point A' after rotating 90 degrees clockwise about the point (0,1) are (3, -4).

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[3r-15] if r is less than 5

Answers

When r is less than 5 and we substitute r = 4 into the expression [3r-15], the result is -3.

The expression [3r-15] represents an algebraic expression that depends on the value of r. The condition given is that r is less than 5. To evaluate this expression, we substitute the value of r into the expression and simplify it.

Given that r is less than 5, let's substitute r = 4 into the expression:

[3(4) - 15]

= [12 - 15]

= -3

Therefore, when r is less than 5 and we substitute r = 4 into the expression [3r-15], the result is -3.

It's important to note that this answer is specific to the given condition that r is less than 5. If the condition changes or if r is greater than or equal to 5, the result of the expression may be different.

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What is the approximate distance from the origin to the point (−5, 6, −1)? Round to the nearest tenth. A) 3.2 units B) 3.5 units C) 7.7 units D) 7.9 units

Answers

Answer:

7.9.

Step-by-step explanation:

Use the Pythagorean Theorem.

√((-5)^2 + (6)^2 + (-1)^2) = √62 = 7.87 = 7.9.

Answer:

Step-by-step explanation:

7.9

Why is 2x 3/4 less than 2?

Answers

Answer & Step-by-step explanation:

It is less because 2 times 3/4 is the same as 2/1 times 3/4 which is 6/4 then simplify it and you get 3/2 which then is 1 1/2.

That is why 2 times 3/4 is less than 2.

Hope that helps ;)

help me plz asap i need this

help me plz asap i need this

Answers

Answer:

circumference=28 in. after doing rounf off to the nearest hundredth

Step-by-step explanation:

Either it’s 28.26 or 28.27, I’m not really sure which one is right

For each pair of functions f and g below, find f(g(x)) and g (f(x)).
Then, determine whether fand g are inverses of each other.
Simplify your answers as much as possible.
(Assume that your expressions are defined for all x in the domain of the composition.
You do not have to indicate the domain.)

f(x) = x+4
g (x) = x+4

Answers

The Function  f(g(x)) = g(f(x)) = x + 8.

The functions are: f(x) = x + 4 and g(x) = x + 4. We can find f(g(x)) by substituting g(x) in place of x in f(x).

f(g(x)) = f(x + 4) = (x + 4) + 4 = x + 8

Similarly, we can find g(f(x)) by substituting f(x) in place of x in g(x).g(f(x)) = g(x + 4) = (x + 4) + 4 = x + 8

Thus, we can see that f(g(x)) and g(f(x)) are equal to each other,

which is x + 8.

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Determine whether the following statement is true or false. The union of two sets is the sets of all elements that are common to both sets

Answers

The answer us true.

Henry made a shirt using 1/3 yards of yellow fabric and 1/2 yards of red fabric. How many yards of fabric did he use in all?
Write your answer as a fraction in simplest form.

Answers

I think that the answer is 123

Which of the following is NOT an elementary row operation?
A. Delete a row of negative numbers
B. Interchange (swap) two rows
C. Add a multiple of one row to another row
D. Multiply a row by a nonzero constant

Answers

Answer:

So your Answer is B.

Step-by-step explanation:

5

There are three types of row operations:

Multiplying a row by a constant c≠0

Adding to a row a different row multiplied by a constant d

Swapping two rows

The third type is of no concern with your question.

Why the limitations on the first two types?

The idea is that row operations should be reversible, so when we perform a row operation, we can perform another one that “undoes” the effect of the previous one. The main reason is that such row operations don't change the solution set of a linear system (translated into matrix form), exactly because the operations are reversible.

Multiplying a row by 0 is not reversible: this should be clear because doing this operation on all rows will yield the null matrix and we surely lose information. Thus is disallowed.

Adding to a row itself multiplied by −1 is the same as multiplying the row by 0, so in general it is disallowed to add a row to itself multiplied by a scalar.

How do you reverse an operation of the first kind? By multiplying the same row by c−1. What for an operation of the second kind? Say we add to row i row j multiplied by d; we reverse this by adding to row i row j multiplied by −d.

The constants c and d can be anything (but for the first type c must be nonzero). Even d=0 is allowed in operations of the second kind: it is just doing nothing, which is of course reversed by doing nothing again.

80 POINTS -Pre Calc Questions

80 POINTS -Pre Calc Questions

Answers

Answer:

x+y=30

2x+3y=80

multiplying equation one by -3 and add equation

-3x -3y=-90

2x +3y=80

2(10)+20(3)=80

80=80

A school bought 105 boxes of chocolate cookies and 22 boxes of vanilla cookies
for a fundraiser. Each box contained 12 cookies.
The school then repacked the cookies into smaller packs of 8 to sell.
How many small packs were there? How many cookies were left over?

Answers

Answer:190 small packs and 4 cookies left over

Step-by-step explanation:

Add the boxes of cookies together 105+22=127

Multiply each box by 12

127 x 12=1524

Because we need to put them into smaller packs of 8 cookies

we need to divide by 8

1524÷8=190 small boxes

This is a total of 190 x 8=1520 cookies there are 4 cookies left over

If it takes 2men 11 days to dig 7 well, how many days should 7men dig 21well

Answers

7 men should be able to dig 21 wells in approximately 4.7 days.

How to determine the number of days

From the question, we have the following parameters that can be used in our computation:

If it takes 2men 11 days to dig 7 well, How many days should 7men dig 21well

We can use the formula:

Number of days = (number of wells * number of days per well) / number of men.

So, we have

Number of days per well for 2 men:

11 days / 7 wells = 1.5714 days per well.

Using the above as a guide, we have the following:

the number of days for 7 men to dig 21 wells:

21 wells * 1.5714 days per well / 7 men = 4.7142days.

Hence, the number of days is 4.7 days.

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Evaluate 2x + 9y -9, when x= 6 and y= 6

Answers

Answer:

57

Step-by-step explanation:

2x + 9y -9

2(6) + 9(6) - 9

12 + 54 - 9 = 57

good luck, i hope this helps :)

Answer:

57

Step-by-step explanation:

2*6+9*6-9=

12+54-9=

66-9=

57

$12 t-shirt; 5% tax.
Please help

Answers

Answer:

13.44

Step-by-step explanation: tax is added after payment so 12 + 5% or 100% + 12% = 112% of 12. There are many ways to solve for this, I used number line starting out because it was easiest for me, just divide 12 by 100 and put that into 1% then multiply that 1% number by 112 and you get 112%.

Answer:

Hello!!

The cost of a $12 t-shirt with 5% tax would be...

$12.60

Step-by-step explanation:

\(12\) × \(0.05=0.6\)

\($12 + 0.6=12.60\)

Hope this helps!!

NEED HELP ASAP! WILL MARK BRAINLIEST TO THE RIGHT ANSWER!! Line A passes through the points (-3,-4) and (-6,-5). Write the equation of the image of A after a dilation with a scale factor of 2, centered at the origin. Write your answer in slope-intercept form.

y=

Answers

Answer:

\(\displaystyle y=\frac{1}{3}x-6\)

Step-by-step explanation:

Dilation of a Line

Given a line that passes through points A(-3,-4) and B(-6,-5). We'll apply a dilation with a scale factor of 2 centered at the origin by multiplying each coordinate by 2. The points map to:

A'(-6,-8) and B'(-12,-10)

Now we find the equation of the line passing through A' and B'.

The equation of a line passing through points (x1,y1) and (x2,y2) can be found as follows:

\(\displaystyle y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)\)

Substituting:

\(\displaystyle y+8=\frac{-10+8}{-12+6}(x+6)\)

\(\displaystyle y+8=\frac{-2}{-6}(x+6)\)

\(\displaystyle y+8=\frac{1}{3}(x+6)\)

Operating:

\(\displaystyle y=\frac{1}{3}x+\frac{1}{3}*6-8\)

\(\displaystyle y=\frac{1}{3}x+2-8\)

\(\boxed{\displaystyle y=\frac{1}{3}x-6}\)

between smokers and nonsmokers, random samples from each group were selected. the sample proportion of people with

Answers

The confidence interval suggests that there is no significant difference in CVD risk between smokers and non-smokers, but any potential difference is likely to be small.

The given confidence interval of (-0.01, 0.04) represents a range of plausible values for the difference in the population proportion of CVD between smokers and nonsmokers, with a 95% level of confidence.

A value of 0 suggests no difference in CVD risk between the two groups Since the interval contains both positive and negative values, we cannot conclude with certainty whether the difference is statistically significant or not.

However, the fact that the interval is relatively small suggests that any difference in CVD risk between smokers and nonsmokers is likely to be small in magnitude.

Therefore, the best interpretation of the interval is that there is no strong evidence to suggest a significant difference in the risk, but any potential difference is likely to be small.

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_____The given question is incomplete, the complete question is given below:

In a large study designed to compare the risk of cardiovascular disease (CVD) between smokers and nonsmokers, random samples from each group were selected. The sample proportion of people with CVD was calculated for each group, and a 95 percent confidence interval for the difference (smoker minus nonsmoker) was given as (−0.01, 0.04). Which of the following is the best interpretation of the interval?

V=Lwh for h equals what

Answers

Step-by-step explanation:

the h stands for height of the cuboid

Answer:

[see below]

Step-by-step explanation:

In the formula for volume of a rectangular prism, the 'h' means the height of the prism given.

V = Length * Width * Height

If you mean what h means algebraically:

\(V = lwh\\\\\frac{V=lwh}{lw}\\\\\frac{V}{lw}=h\\\\\boxed{h= \frac{V}{lw}}\)

Hope this helps.

which inequality will use a solid line in its solution graph?

A) (y<2x) B(y>x) c (y<2x+4) or D(y>2x-5

Answers

In the given options, none of them have inequality sign ≤ and ≥,  so the given inequalities do not have solid line in its solution graph.

What are inequalities?

Inequalities are the mathematical expressions in which both sides are not equal. In inequality, unlike in equations, we compare two values. The equal sign in between is replaced by less than (or less than or equal to), greater than (or greater than or equal to), or not equal to sign.

A solution for an inequality in x is a number such that when we substitute that number for x we have a true statement.

The boundary line for the inequality is drawn as a solid line if the points on the line itself do satisfy the inequality, as in the cases of ≤ and ≥. It is drawn as a dashed line if the points on the line do not satisfy the inequality, as in the cases of < and >.

Hence, in the given options, none of them have inequality sign ≤ and ≥,  so the given inequalities do not have solid line in its solution graph.

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3 6 9 12 15 18 21 24 27 30 is odd or even numbers?​

Answers

Answer: Half of them are even and half of them are odd.

Step-by-step explanation:

The even numbers are 6, 12, 18, 24, and 30. An even number is defined as a number that is divisible by 2, meaning it has no remainder when divided by 2. For example, 6 divided by 2 equals 3 with no remainder, so 6 is even.

The odd numbers are 3, 9, 15, 21, and 27. An odd number is defined as a number that is not divisible by 2, meaning it has a remainder of 1 when divided by 2. For example, 9 divided by 2 equals 4 with a remainder of 1, so 9 is odd.

Therefore, out of the given numbers, half of them are even and half of them are odd.

________________________________________________________

The annual rate, r, it takes for 1 dollar to grow to X dollars in 2 years is given by the formula X = (1+r) ².
Find the rate necessary for a dollar to triple in 2 years.

Answers

The rate of interest is 73%.

What is the annual rate?

The term annual percentage rate of charge refers to the interest rate for an entire year rather than just a monthly fee or rate as applied on a loan, mortgage loan, credit card, etc. It can also be referred to as a nominal APR or an effective APR. It is an annual rate of a finance charge.

Given that 1 dollar to grow to X dollars in 2 years is given by the formula X = (1+r) ².

A dollar to triple in 2 years.

Thus putting X = 3 in X = (1+r) ²

3 = (1+r) ²

Take square root on both sides:

√3 = 1 + r

Subtract 1 from both sides:

r = √3 - 1

r = 0.73

r = 73%

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Sander usually drinks 3 cups of coffee in the morning. How many liters of coffee does he drink? Round your answer to the nearest tenth.

Answers

Answer:

I am not understanding the question ok

In the figure AC and BD bisect each other. The length of AB is 12 centimeters and the length of BC is 11 centimeters. The length of AD is ___ centimeters and the length of DC is ___

In the figure AC and BD bisect each other. The length of AB is 12 centimeters and the length of BC is

Answers

Answer:

AD = 11 cmDC = 12 cm

Step-by-step explanation:

Triangles AEB and CED are congruent as per SAS theorem since two sides are congruent and included angles are same as vertical angles

Therefore AB = DC = 12 cmSimilarly, BC = AD = 11 cm

Answer: AD = 11 cm

DC = 12 cm

Step-by-step explanation:

Please answer this correctly without making mistakes

Please answer this correctly without making mistakes

Answers

Answer: 4.3 mi

Step-by-step explanation:

From Oxford, getting to Kingswood takes 7.5mi, and getting to Norwood takes 11.8mi.  Thus, simply do 11.8-7.5 to get 4.3mi.

Hope it helps <3

Under Todd’s new cable television plan, his bill averages $63 per month. This is 140% of his average monthly bill last year when he had the basic cable package. What was his average monthly cable bill last year?

Answers

Answer:

45

Step-by-step explanation:

translation :

140% of x = $63

x = $63 ÷ 1.4

x = $45

FUN FACTS :

interesting: 100% means double that number or times 2

if a price is $20 & it increases 100% in price that means its $20 times 2 or $40

percent means per 100

cent means 100 in latin

that's why the decimal moves 2 spaces

for the 2 zeros in 100

chatgpt

Find five solutions of the equation. Select integer values for x, starting with 2 and ending with 2. Complete the table
of values below.
y = 6x-4
...
Complete the table to the right by typing an integer for
the first input and an ordered pair for the second input.
X
-2
-1
0
1
2
y = 6x-4
(x,y)

Answers

The second inputs are -16 , -10 , -4, 2 ,8   an integer.

What in math is an integer?

An integer, pronounced "IN-tuh-jer," is a whole number that can be positive, negative, or zero and is not a fraction. Integer examples include: -5, 1, 5, 8, 97, and 3,043. 1.43, 1 3/4, 3.14, and other numbers that are not integers are some examples.

     x                                      y = 6x - 4                                                      (x,y )                                                                                                                        

  -2                                           6 * -2 - 4                                         ( -2 , - 16)

______________________________________________________

   - 1                                          - 1 * 6 - 4                                         ( -1 , -10 )

________________________________________________________

   0                                           0 * 6 -4                                            ( 0 , -4)

________________________________________________________

     1                                          6 * 1 - 4                                             ( 1 , 2)

________________________________________________________

    2                                           6 * 2 - 4                                          ( 2 , 8 )

_______________________________________________________

the second inputs are -16 , -10 , -4, 2 ,8

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The complete question is -

Find five solutions of the equation. Select integer values for x, starting with - 2 and ending with 2. Complete the table of values below y =6x-4 (x,y) Complete the table to the right by typing an integer for the first input and an ordered pair for the second input. х y = 6x-4 (x,y) -2 - 1 0 1 2 Use two of the given points to graph the equation. Click to enlarge graph

what is the mean of 61, 55, 66, 58, 50, 70​

Answers

Answer:

Mean: 60

Step-by-step explanation:

First of all, in order to find the mean, one must add all the numbers together (61,55,66,58,50,70), which would give a total of 360.

After that, divide that total by the quantity of numbers (in other words, the total number of numbers, which in this case is 6). So, you would have to divide 360 by 6 leading to an answer of 60(the mean, which in other words is like finding the average).

20 workers can produce 1000 products in 10 hours.
Assuming the efficiency per worker remains the same, how many products can 15 workers produce in 5 hours?

Answers

Using proportions, it is found that 375 products are produced with 15 workers in 5 hours.

What is a proportion?

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

In this problem, we have that the rule of three are given as follows:

1000 products - 20 workers - 10 hours.

x products - 15 workers - 5 hours.

The measures are direct proportional, hence:

\(\frac{1000}{x} = \frac{20}{15} \times \frac{10}{5}\)

\(\frac{1000}{x} = \frac{40}{15}\)

Applying cross multiplication:

40x = 15(1000)

x = 15(1000)/40

x = 375.

375 products are produced with 15 workers in 5 hours.

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a cup holds d ml of tea. a student drinks on fifth of the tea. how much tea is left

Answers

The amount of tea that is left after the student has drank is; ⁴/₅d mL

How to solve fraction word problems?

In word problems on fractions, what we do is that we will solve different types of problems on multiplication of fractional numbers and division of fractional numbers.

For example;

4/7 of a number is 84. Find the number.

Since 4/7 of a number = 84

The, the Number = 84 × 7/4

Number = 147

Now, in this question, we are given;

Quantity of tea in cup = d ml

Amount of tea a student takes out to drink = ¹/₅ of the quantity in the cup.

Thus;

Amount of tea left = d - ¹/₅d

Amount of tea left = ⁴/₅d

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the nurse teaches a group of nursing students about informed consent for medical treatment. the nurse includes teaching about informed consent involving minors. which statement is correct for the nurse to include in the teaching? What does "misstate" mean? pls ansdwerwoth 30 poitnsss is the moon accelerating as it orbits the earth? explain your reason 2019 texakalidis combined radial to axillary and spinal accessory nerve (san) to suprascapular nerve (ssn) transfers may confer superior shoulder abduction compared with single sa to ssn.pdf pls asap Casey's teacher needs to give him feedback on his history essay, including about his grammar and spelling. What's the MOST likely way they'll deliver this feedback?Question 1 options:by writing comments on his paperby verbally telling him all the things they found wrongby creating a memo about the changesby sending him a text Out of 50 students in a class,10 student like maths but not science and 15 students like science but not maths.if 10 students like neither of both subjects find the ratio of the students who like maths or science The duration and capacity of short-term memory are best described as ____.a. small in capacity and long in durationb. large in capacity and short in durationc. large in capacity and long in durationd. small in capacity and short in duration The highlighted bands (magenta) in the gel were hybridized with a probe for the gene pep during a Southern blot. Where in the gel is the pep gene located Discuss how the use of digital formats for audio-visual recording and editing hastransformed the film world. Scientists are interested in determining if selenium, from a nearby mine, magnifies in the tissues of fish living in a lake Which of the following best describes a testable hypothesis for the study? Tissue from fish in the lake will have a higher level of selenium than tissue from fish in a nearby take O Fish will have a higher concentration of selenium than mercury in their tissues O Selenium will be at a higher concentration in fish tissue than in the tissue of fish prey. O Selenium will be at a higher concentration in acid mine drainage than in fish tissues If there _____ (be) any tickets left for the concert, ___ you ____ (buy) two for me and Tom? (correct the sentence) In which city did the residents of a ghetto stage a brave uprising in 1943? a. warsaw b. amsterdam c. berlin d. budapest Find the length of the side and Ill give brainlyist Solve the following equation without using a calculator. List all possible solutions between [0,2). tan()=3O a = {/3}O a = {/3, 2/3, 4/3, 5/3}O a = {/3, 4/3}O a = {/3, 2/3} Hydrogen was collected over water using the approach in the manual. The water temperature was 220C and the measured pressure inside the tube was determined to be 715mmHg. Use Appendix F in your lab manual to determine the pressure of the collected hydrogen gas. Find the distance between the points J(-8, 0) and K(1,4). Answer my question plzzz!!What is the theme?ANDWhat is the topic and the message of the story? (30 Points) _____ in how the measuring cup is filled can greatly impact how much of that ingredient fits in the cup. A. MechanicsB. VariationC. StrainD. Terminology sketch a pavement serviceability curve, label the axes, and indicate initial and terminal serviceability