PLEASE HELP: The exact value of cos 13π/8 is: A. 0.99. B. √2- √2/4 c. √2+√2/4 D. 0.38.​

Answers

Answer 1

The exact value of cos(13π/8) is 1/2 [tex]\sqrt{2-\sqrt{2} }[/tex].

What is trigonometric ratio?

Trigonometriic ratios are the ratios of the sides of a right angled triangle. sin , cos, tan, sec, cosec, cot are some of the trigonometric ratios. Sin is the ratio of perpendicular and hypotenuse, cos is the ratio if base and hypotenuse, tan is the ratio of perpendicular and base, secant is the ratio of hypotenuse and base, cosecant is the ratio of hypotenuse and perpendicular, cot is the ratio of base and perpendicular.

How to find value?

We have to find the value of cos (13π/8).

We have to use formula which is following:

cos[tex]Θ[/tex]=[tex]\sqrt{1/2(1+cos 2Θ}[/tex]

=[tex]\sqrt{1/2(1+cos(2*13 π/8)}[/tex]   (π=[tex]π[/tex])

=[tex]\sqrt{1/2(1+cos(3 π+π/4)}[/tex]

=[tex]\sqrt{1/2(1-cos(π/4)}[/tex]

=[tex]\sqrt{1/2(1-1/\sqrt{2} }[/tex]

=[tex]\sqrt{\sqrt{2}-1/2\sqrt{2} }[/tex]

=1/2[tex]\sqrt{2-\sqrt{2} }[/tex]

Hence the value of cos (13π/8) is [tex]1/2\sqrt{2-\sqrt{2} }[/tex].

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Related Questions

Mention any two similarities between rectangle and square.​

Answers

Squares and rectangles both are a type of quadrilateral, both have their four interior angles equal to 90 degrees and opposite sides parallel to each other.

The similarities between a rectangle and a square as:

All 4 angles are 90 deg each.

Opposite sides are parallel and equal.

The diagonals bisect each other.

Circles can circumscribe both figures.

The diagonals form the diameter of the circumscribing circle.

The square root of the sum of the squares of adjacent sides is the diagonal.

The area is the product of adjacent sides.

The diagonals bisect the figure into 2 congruent triangles.

Join the midpoints of opposite sides and you get 4 similar figures of 1/4 the area of the original figure.

Join the midpoints of 4 sides in order and you get a rhombus, whose area is half that of the original figure.

If bob gives away 7 blocks, he will have 12 left. How many blocks did he have originally

Answers

Answer:

h

Step-by-step explanation:

19 blocks

Answer:

original blocks  =19

Step-by-step explanation:

original blocks -7 =12

Add 7 to each side

original blocks -7+7 =12+7

original blocks  =19

A rectangle is 1 1/2 length and 4 1/4 width what is the area of rectangle




The numbers are a whole and a fraction that’s why there is a space

Answers

Answer:

6 3/8 units

Step-by-step explanation:

1 1/2* 4 1/4= 6 3/8

Can you help and do it step by step

Answers

Answer:

$4800

Step-by-step explanation:

SI=PRT DIVIDED BY 100..

So it is going to be 400×2×6 divided by 100 which will be 4800

How many inches is the circumference of this circle?

Type in your answer WITH NO LABEL, JUST THE NUMBER.

Answers

Answer:

Diameter(line going across the circle that you've given) = 6 in

Radius(half of diameter) = 3 in

Circumference(the perimeter of the circle) = 18.85 in

Area = 28.27^2

Step-by-step explanation:

In order to find the circumference, you will need to first find the radius(which is always half the size of the diameter which in this case is 3 in). You will then need to do this formula: 2 x 3.14 x 3 which equals to 18.85.

Answer:

The circumference of a circle is about 18.85 inches.

Step-by-step explanation:

The radius is always half of the diameter, and the diameter is 6 inches.

6 divided by 2 is 3, so the radius of this circle is 3 inches.

The formula for circumference of a circle is :

C = 2πr = 2 · π · 3 ≈ 18.84956

The circumference of a circle is about 18.85 inches.

Plzzz someone help i just need the formula

Answers

Answer:

[tex]S(y)=36000*(1+0.03)^{y}[/tex]

Step-by-step explanation:

Answer:

y=36,000×1.03^x

Step-by-step explanation:

Write the equation of the line passing through the point (−3,−4) that is perpendicular to y=8/3x+5.

Answers

Answer:

y = -3/8x -41/8

Step-by-step explanation:

Perpendicular lines intersect at 90° and their slopes are opposite reciprocals.

Therefore the slope changes from 8/3 to -3/8.

Now we must solve for the new y-intercept (b) by plugging in the given coordinate (-3,-4).

The result is b = -41/8 so our new equation is:

y = -3/8x -41/8

How many sides does a regular polygon have if each exterior angle measures
20?

Answers

Answer:

18 sides

Step-by-step explanation:

Each exterior angle of a regular polygon = 20 deg. So the polygon has 360/20 = 18 sides

Help pleaseeeee will give brainliest

Answers

Answer:

q.12

angle ACB=180-123

therefore ACB=57

again 5x-15+7x+6+57=180

or,12x+48=180

or,x=132/12

or x=11

What is the surface area and volume of the sphere shown below?
Your response should show all necessary calculations and diagrams.

Answers

Answer:

ur mom

Step-by-step explanation:

doin doin

Which is the better value for money 250g of coffee R12,35 or 450g of the same coffee at R21,95

Answers

Answer:

450g coffee or 21.95$ coffee

Step-by-step explanation:

again, divide whichever pair you want to and you still have the same answer whether it is less or more: 450/250 is math would be 9/5 and 21.95/12.35 is 1.77732793522. so if we find the true value of 9/5, which is 1.8, and since it is more that the original price that means the more coffe you get, the cheaper it gets (basically all of life is like this), so the 450 g coffee is worth alot less than and is bigger than the 250 g coffee

Easy question please help

Answers

Answer:

[tex]y = 3x - 2[/tex]

Step-by-step explanation:

Required

The equation of the above linear function

From the table, we have:

[tex](x_1,y_1) = (1,1)[/tex]

[tex](x_2,y_2) = (2,4)[/tex]

Calculate slope (m)

[tex]m = \frac{y_2 -y_1}{x_2 -x_1}[/tex]

[tex]m = \frac{4 -1}{2 -1}[/tex]

[tex]m = \frac{3}{1}[/tex]

[tex]m =3[/tex]

The equation is:

[tex]y = m(x - x_1) + y_1[/tex]

So, we have:

[tex]y = 3(x - 1) + 1[/tex]

[tex]y = 3x - 3 + 1[/tex]

[tex]y = 3x - 2[/tex]

A random sample of 30 patties that were inspected over the course of the last week revealed that the average weight was 95.0 grams. The standard deviation was 0.25 grams. What percentage of the deliveries is likely to be outside the specification limits (outside the interval of [94.5, 95.5])

Answers

Answer:

4.56% of the deliveries are likely to be outside the specification limits.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

The average weight was 95.0 grams. The standard deviation was 0.25 grams.

This means that [tex]\mu = 95, \sigma = 0.25[/tex]

What percentage of the deliveries is likely to be outside the specification limits (outside the interval of [94.5, 95.5])?

Less than 94.5, or more than 95.5. Since the normal distribution is symmetric, these probabilities are the same, so we can find one of them and multiply by two.

The probability that it is less than 94.5 is the p-value of Z when X = 94.5. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{94.5 - 95}{0.25}[/tex]

[tex]Z = -2[/tex]

[tex]Z = -2[/tex] has a p-value of 0.0228

2*0.0228 = 0.0456

0.0456*100% = 4.56%

4.56% of the deliveries are likely to be outside the specification limits.

Which expression is equivalent to 1/2x + 8

Answers

Answer:

1/2( x+16)

Step-by-step explanation:

1/2x + 8

Factor out 1/2

1/2*x + 1/2 *16

1/2( x+16)

use the diagram below to find all missing angles

Answers

Answer:

Step-by-step explanation:

Soooo, angle 1 is 157 degrees

That means:

Angle 2 is 23 degrees                                   Supplementary Angles

Angle 3 is 157 degrees                                  Vertical Angle to Angle 1

Angle 4 is 23 degrees                                   Vertical angle to Angle 2

Answers:

angle 2 = 23 degreesangle 3 = 157 degreesangle 4 = 23 degrees

=======================================================

Explanation:

Angles 1 and 2 are supplementary as they form a straight line. So the angles add to 180

(angle1)+(angle2) = 180

angle2 = 180-(angle1)

angle2 = 180-157

angle2 = 23 degrees

Angle 4 is congruent to this because angles 2 and 4 are vertical angles. Vertical angles are always congruent. Note how angles 1 and 4 are supplementary.  

Since angles 1 and 3 are the other pair of vertical angles, this must mean angle 3 is 157 degrees.

Shana has three pets, a dog, a cat and a bird. One of them is named Sammy. Noodles is younger than both the bird and the dog. Fluffy is green. Which pet has the name Sammy?

Answers

Answer:

The dog has the name Sammy.

Step-by-step explanation:

A cat and dog cannot be green, therefore the bird is Fluffly.

Noodles must be the cat since it's younger than the bird and the dog.

The only one that doesn't have an explanation is the dog, therefore the dog must be named Sammy.

Find the slope from the given equation. 9y = -3x + 5

Answers

Answer:

-3/9x

Step-by-step explanation:

You rearrange for 'y' so divide both sides by it's coefficient which is 9.

Answer:

The slope is -1/3


To prove ABC= ADC, To prove which triangle postulate could you use?

SSS
SAS
ASA
AAS

Answers

Answer:

ASA

Step-by-step explanation:

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

To prove ABC = ADC, We use ASA triangle postulate.

What is congruency?

We know two similar planer figures are congruent when we have sides or angles or both that are the same as the corresponding sides or angles or both.

The similarity of triangles on the other hand is when the corresponding angles are equal but the corresponding sides are not equal but they have the same common ratio.

From the given diagram a quadrilateral ABCD is given,

Line segment AC divides quadrilateral ABCD into two triangles namely

ABC and ADC, and both have a common side AC.

m∠BAC ≅ m∠DAC and m∠BCA ≅ m∠DAC.

Therefore, Triangle ABC and ADC are congruent by ASA, with two angles and a side included between them.

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If RT is 10 centimeters long, what is ST?

Answers

Answer:

Answer: a

Step-by-step explanation:

Answer:

6

Step-by-step explanation:

First, find x

RT = 2x + 3x

10 = 2x+3x

10 = 5x

10/5 = 2

Now place 2 in place of x in the line ST

ST = 3x

ST = 3 * 2

ST = 6

A grocery store manager notices that this month her store sold a total of 521 gallons of ice cream, which represents a decrease of 10% from last month. On the other hand, her store sold 791 pounds of broccoli this month, which represents an increase of 25% from last month. How much ice cream and broccoli did the store sell last month? Round your answers to the nearest integer.

Answers

Answer:

Last month the grocery store sold 578.88 gallons of ice cream and 632.8 pounds of broccoli.

Step-by-step explanation:

Since a grocery store manager notices that this month her store sold a total of 521 gallons of ice cream, which represents a decrease of 10% from last month, and on the other hand, her store sold 791 pounds of broccoli this month, which It represents an increase of 25% from last month, to determine how much ice cream and broccoli did the store sell last month, the following calculation must be performed:

Ice cream = 100 - 10 = 90

90 = 521

100 = X

100 x 521/90 = X

52,100 / 90 = X

578.88 = X

Broccoli = 100 + 25 = 125

125 = 791

100 = X

100 x 791/125 = X

79,100 / 125 = X

632.8 = X

Therefore, last month the grocery store sold 578.88 gallons of ice cream and 632.8 pounds of broccoli.

The summit of a volcano is 5 kilometers (km) above sea level, as shown below.
If the ocean floor has an elevation of -5 kilometers, which statement describes
the distance of the summit and the ocean floor?
It's not 0 or 5

Answers

Well 5 is -10 km away from -5. We can further prove this by adding -5 + 10, giving us 5. Answer is 10!

The sum of two numbers in 106 and the greater exceeds the lesser in 8. Find the numbers.

Answers

Step-by-step explanation:

51 and 51

maybe

hope it help u

Simplify: -8x +7-5-5x + 5x
A
- 8x + 2
B
-18x+12
-x-5
D
-X+12

Answers

Answer:

A) -8x+2

Step-by-step explanation:

-8x + 7 - 5 - 5x + 5x

-8x -5x + 5x + 7 - 5

- 8x+2

PLEASE HELP ASAP WILL GIVE BRAINLEIST FOR AN ACTUAL ANSWER

Answers

Answer:

<V = 40

Step-by-step explanation:

The exterior angle is equal to the sum of the opposite interior angles

20x = 60+7x+5

Combine like terms

20x = 7x+65

Subtract 7x from each side

20x -7x = 7x+65-7x

13x = 65

Divide each side by 13

13x/13 = 65/13

x = 5

<v = 7x+5 = 7*5+5 = 35+5 = 40

answer:

it's U = 60°

V = 50°

T = 70°

Help me please I NEED to pass this

Answers

OPTION C is the correct answer.

Hope it helps you.

Find the value of the variable(s). If your answer is not an integer, leave it in simplest radical form.
5
60°
10
x
Not drawn to scale

Answers

Answer:

D

5 sq.rt. 3

Step-by-step explanation:

use the pythagorean theorem: a^2 + b^2 =c^2

5^2 + x^2 = 10^2

25+ x^2 =100

x^2 = 100 - 25

x^2 =75

x = [tex]\sqrt{75}[/tex]

x = 5 [tex]\sqrt{3}[/tex]

A construction crew is lengthening a road that originally measured 47 miles. The crew is adding one mile to the road each day. Let L be the length (in miles) after D days of construction. Write an equation relating L to D. Then use this equation to find the length of the road after 31 days.

Answers

Answer:

78 miles

Step-by-step explanation:

Given that:

Original length, L = 47 miles

Additional length (miles) added per day, = 1 mile

Representing as an equation :

L(D) = original length + additional length per day * number of days

Let, D = number of days

L(D) = 47 + D

Length after 31 days :

L(31) = 47 + 31

= 78 miles



Jared flicked the arrow on this spinner four times, and the arrow landed on green each time. If Jared spins the arrow a fifth time what is the theoretical probability that it will land on green

Answers

Answer:

The correct answer would be 3/8.

Step-by-step explanation:

There are 3 greens on this spinner , and 8 in total , so there’sa probability of 3% that the arrow will land on green again .

The theoretical probability that it will land on green is 1.

What is the probability?

It is the likeliness of happening an event. It is calculated by the following formula:

Probability=number of events/number of total events.

How to calculate the probability?

Jared had flicked the arrow all the four times on the green ,it means that the probability that it is landed on green each time is 100%. So the probability that it will land on green fifth time also is 1.

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how to write expression for The product of ten less than a number and the number

Answers

Answer:

x-10

Step-by-step explanation:

ten is less than x

follow me for more answer

the ratio of the following 30 minutes to 2 hours.

Answers

Answer:

30 minutes to 120 minutes.

Step-by-step explanation:

Answer:

2 hrs=120 min

30:120=1:4

Step-by-step explanation:

ans is 1:4

marke brainliest plzzzzzzz

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