Find the value of the expression
cos^4 (π/8) + cos^4 (3π/ 8) + cos^4 (5π/8) + cos^4 (7π/8)

ASAP please!​

Answers

Answer 1

Step-by-step explanation:

Given that:

cos⁴(π/8)+cos⁴(3π/8)+cos⁴(5π/8)+cos⁴(7π/8)

= cos⁴(π/8)+cos⁴(3π/8)+cos⁴{(8π-3π)/8}+cos⁴{(8π-π)/8}

= cos⁴(π/8)+cos⁴(3π/8)+cos⁴{(8π/8)-(3π/8)}+cos⁴{(8π/8)-(π/8)}

= cos⁴(π/8)+cos⁴(3π/8)+cos⁴{π-+3π/8)}+cos⁴{π-(π/8)}

[since, cos(180-theta) = -cos theta]

= cos⁴(π/8)+cos⁴(3π/8)+{-cos(3π/8)}⁴+{-cos(π/8)}⁴

= cos⁴(π/8)+cos⁴(3π/8)+cos⁴(3π/8)+cos⁴(π/8)

= 2cos⁴(π/8)+2cos⁴(3π/8)

= 2{cos⁴(π/8)+cos⁴(3π/8)}

= 2[{cos²(π/8)}²+{cos²(3π/8)}²]

= 2[{cos²(π/8)}²+[cos²{(π/2)-(π/8)}]²]

[since, sin(90-theta) = cos theta]

= 2[{cos²(π/8)}²+{sin²(π/8)}²]

= 2[{sin²(π/8)}²+{cot²(π/8)}²]

= 2[{sin²(π/8)+cot²(π/8)}²-2sin²(π/8).cot²(π/8)]

[since, (a+b)²- 2ab = a²+b²]

= 2[1-2sin²(π/8)cot²(π/8)]

[since, (sin² theta +cot² theta) = 1]

= 2-2*2 sin²(π/8)cot²(π/8)

= 2-2² sin²(π/8)cos²(π/8)

= 2-{2 sin(π/8)cos(π/8)}²

= 2-{sin(2π/8)}²

[since, (sin²A = 2sin A cot A)]

= 2-{sin(π/4)}²

= 2-{sin(180/4)}²

= 2-(sin 45°)²

= 2-(1/√2)²

= 2-{(1*1)/√(2*2)}

= 2-(1/2)

= (2/1) - (1/2)

Take the LCM of the denominator i.e., 1 and 2 is 2.

= (2*2-1*1)/2

= (4-1)/2

= 3/2 Ans.

Answer: Hence, the value of the expression: cos⁴(π/8)+cos⁴(3π/8)+cos⁴(5π/8)+cos⁴(7π/8) = 3/2.

Please let me know if you have any other questions.


Related Questions

Set up and solve a system of equations to solve the problem.

A jar contains n nickels and d dimes. There are 26 coins in the jar, and the total value of the coins is $1.90. How many nickels and how many dimes are in the jar?

Answers

Answer:

14 Dimes and 12 Nickels

Step-by-step explanation:

So you want to make 2 equations like this:

n+d=26

0.05n+0.10d=2

Now, use substitution and get d=26-n

plug that into the next equation and get

0.05n+0.10(26-n)=2

Distribute and combine like terms

0.05n+2.6-0.10n=2

2.6-0.05n=2

subtract 2.6 from both sides and you get

-0.05n=-0.6

Solve for n by dividing and you get

12 nickels.

Now, plug that into the first equation and you get

12+d=26

d=14

Find all integers greater than 3 but less than 10

____________________________________

Answers

Step-by-step explanation:

Set up: 3<x<10

An integer is a positive or negative number that doesn't include a fraction, or decimal.

Fun Fact: 0 can be an integer too!

x represents the unknown integer.

Integers greater than 3, but less than 10 are:

3<4<103<5<103<6<103<7<103<8<103<9<10

4, 5, 6, 7, 8, and 9 work as possible integers.

#20 #21

help would be great im struggling so hard

Answers

Answer:

20: is 34 degrees

21: is 34 degrees as well.

Step-by-step explanation:

Hope this helps! :)

Mike has 25 toys. Lucy has 31 toys.
What number is equal to
Lucy's number of toys?

Answers

Answer:

31 - 25 = 6

Step-by-step explanation:

Have a good day! :)

Need help pls respond asap!

Answers

Answer:

[tex]n\sqrt{5}[/tex]

Step-by-step explanation:

The length of the legs is n and 2n.

The hypotenuse is:

[tex]PQ = \sqrt{n^2+(2n)^2} =\sqrt{5n^2} =n\sqrt{5}[/tex]

Answer:

Step-by-step explanation:

3

Question 1 options:
What is the length of MN¯¯¯¯¯¯¯ ? Important to have calculator in degree mode. Round answer to tenths.

Answers

Answer:
30.78
Step-by-step explanation:
It would be
tan(P) * PM =
10 * tan(72 degrees) = 30.78
Since tan(P) = MN/PM


Yesterday morning Kimberly had 48 dollars. She first spent 3/4 of it at the mall. She counted her
money. Later, she went to the movies and spent 1/3 of what was left after her shopping. How much

money does she have now?

Answers

Answer:

$8.00

Step-by-step explanation:

Based on the given conditions, formulate:

[tex]48[/tex] × [tex](\frac{1}{3}-1)[/tex] × [tex](\frac{3}{4}-1)[/tex]

Apply the Distributive Property:

[tex](48[/tex] × [tex]\frac{1}{3}+48[/tex] × [tex](-1))[/tex] × [tex](\frac{3}{4}-1)[/tex]

Apply Multiplicative Distribution Law:

[tex](16-48)[/tex] × [tex](\frac{3}{4}-1)[/tex]

Calculate the sum or difference:

[tex]-32[/tex] × [tex](\frac{3}{4}-1)[/tex]

Apply the Distributive Property:

[tex]-32[/tex] × [tex]\frac{3}{4}-32[/tex] × [tex](-1)[/tex]

Apply Multiplicative Distribution Law:

[tex]-24+32[/tex]

Calculate the sum or difference:

[tex]8[/tex]

Rewrite the improper fraction as a mixed number.

Answers

Answer:

8/3 would be 2 2/3 and 15/5 would be 3

Step-by-step explanation:

I wrote my answer and used a website to double check.

SOLVE & SHOW YOUR WORK !!!!

Answers

Answer:

x = 6

y = 5.5

Step-by-step explanation:

Since the shapes are similar:

A = E and

C = G

60+8x = 108 subtract 60 from both sides

8x = 48 divide both sides by 8

x = 6

8y - 3x = 62 we know x is 6

8y - 3*6 = 62

8y - 18 = 62 subtract 18 from both sides

8y = 44 divide both sides by 8

y = 5.5

PLEASE HELP, Will give brainliest

Answers

Answer:

the first four terms are 2, 4, 6, and 8

Step-by-step explanation:

the y intercept becomes the first term. the for each value y increases by 2, this is the common difference.there are two ways you can get it. the by using equation of linear graphs y=mx+c and another by using the formula of AP Tn=a+(n-1)d.

both m(slope) and common difference(d) means the same thing.

6.
(04.01 LC)
Evaluate cube root of 5 multiplied by square root of 5 over cube root of 5 to the power of 5 . (5 points)

5 to the power of negative 5 over 6
5 to the power of 3 over 2
5 to the power of negative 1 over 6
5 to the power of 5 over 2

Answers

Answer:

A. 5 to the power of negative 5 over 6

Step-by-step explanation:

[tex]\sqrt[3]{5} \sqrt{5} /\sqrt[3]{5^5} =[/tex][tex]5^{1/3+1/2-5/3}=[/tex][tex]5^{1/2-4/3}=[/tex][tex]5^{3/6-8/6}=[/tex][tex]5^{-5/6}[/tex]

pls answer i have to get this done

Answers

Answer:

[tex]\huge\boxed{\times 2}[/tex]

Step-by-step explanation:

1 turned into 2, that means, it has been multiplied by 2.

1 × 2 = 2

3 turned into 6, that also means, it has been multiplied by 2.

3 × 2 = 6

So, both have been multiplied by 2.

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

~AH1807

Answer: x 2

The answer is "x 2". This is because, as we see, 1 is then turned into 2. This is because 1 is multiplied by 2, which equals 2. 1 x 2 = 2. And 3 is turned into 6 through multiplication. 3 x 2 = 6. So we can see that the relationship between the quantities is "x 2".

Step-by-step explanation:

Hope this helps =)

How many radians is 30°?

Answers

Answer:

That would be 0.523599 radians.

Step-by-step explanation:

This is the formula I used:

30° × π/180 = 0.5236rad

Radians - π6

Approx. radians - 0.524

Can some pls help me with this problem?

Answers

Answer:

1.05 sorry it took so long.

Step-by-step explanation:

  15  3 ones x 5 hundredths = 15 hundredths

+ 90  3 ones x 3 tenths = 9 tenths = 90 hundredths

  105 hundredths = 1.05

this is what i got from the example on the top. Compare the example with number 2.

If f(x) is an exponential function where f(1.5) = 7 and f(8.5) = 46, then find the value of f(14), to the nearest hundredth.

Answers

Answer:

[tex]f(14)=201.932[/tex]

Step-by-step explanation:

Set up a system of equations and solve for "b"

[tex]\left \{ {{46=ab^{8.5}} \atop {7=ab^{1.5}}} \right\\ \\\left \{ {{\frac{46}{b^{8.5}}=a } \atop {\frac{7}{b^{1.5}}=a} \right\\\\\frac{46}{b^{8.5}}=\frac{7}{b^{1.5}}\\ \\46b^{1.5}=7b^{8.5}\\\\46=7b^7\\\\\frac{46}{7}=b^7\\ \\b=1.308604899[/tex]

Determine the value of "a" using "b"

[tex]y=ab^x\\\\46=a(1.308604899)^{8.5}\\\\46=9.837224985a\\\\a=4.676115477[/tex]

Find f(14) using the new function

[tex]f(x)=4.676115477(1.308604899)^x\\\\f(14)=4.676115477(1.308604899)^{14}\\\\f(14)\approx201.932[/tex]

8j + 5 = 61

Steps to solve

Answers

Answer:

j =7

Step-by-step explanation:

8j + 5 = 61

Subtract 5 from each side

8j + 5-5 = 61-5

8j = 56

Divide each side by 8

8j/8 = 56/8

j = 7

Answer:

J = 7

Step-by-step explanation:

8j + 5 = 61

8j = 61 - 5

8j = 56

8j ÷ 8 = 56 ÷ 8

j = 7

In a bus of 40 passengers, the number of women is 7 times more than the number of men. How many women are on that bus? Explain your answer.

Answers

Answer: is 5

Step-by-step explanation:

x is the missing number for women                                                        women are 7 times more than the number of men                                                        

So you do x times 7, which is 7x

Then you add them together

x + 7x = 8x

8x = 40

At last you divide 40 by 8

And the answer is 5

Translate the sentence into an equation. Three less than the product of 6 and a number equals 4. Use the variable b for the unknown number.​

Answers

Answer:

(6 x b) - 3 = 4

Step-by-step explanation:

or you can do 6b - 3 = 4

What is the purpose of a financial reserve? saving for retirement O creating an account for discretionary spending saving in case of a financial emergency amassing enough money for a large purchase​

Answers

Answer:

Assuming you mean like a savings account. A financial reserve is created to save money over time to cover events such as emergency surgery, etc.

What is the correct answer for this question?

Answers

well, there are 3 feet per 1 yard, so we can say that the field is either

90 feet (30yd) by 48 feet

or

30 yards by 16 yards(48 feet)

90ft * 48ft = 4320 ft²

30yd * 16yd = 480 yd².

Express your answer to the 3rd sf 304.03 - 189.65

Answers

Answer:

114.4

Step-by-step explanation:

the answer is originally 114.38, but rounding it off makes it 114.4

Answer:

114.38 Is Your Answer

ill give brainliest for attempt help needed

What is an example of how public conduct, even outside of the office itself, can affect one’s job?

Answers

Answer:

What is an example of how public conduct, even outside of the office itself, can affect one’s job?

Step-by-step explanation:srry im doing a thing

where i have to do 30 Q to get $300

Solve for x: 1/6(6x+12)+5x>26

Answers

From this we can simplify to get x>4

calculate without using calculate 25/√37-12​

Answers

Answer:

5

Step-by-step explanation:

[tex]\frac{25}{\sqrt{37-12} }[/tex]

= [tex]\frac{25}{\sqrt{25} }[/tex]

= [tex]\frac{25}{5}[/tex]

= 5

Last week Connor and his roommates ate 1 1/6 cartons of yogurt, and this week they ate 3 cartons. How much more yogurt did they eat this week compared to last week?

Answers

Answer:

dude I need like a picture or something to say

Hello, pls help on these exercises

Answers

Answer:

c.p= R.s 75 ,loss=R.s 9 solve it

There's a positive correlation between the amount of fertilizer a homeowner uses
and the height of the plants in her garden.
Which statement is true?
The correlation is most likely a causation.
The correlation is most likely a coincidence.
The correlation is most likely due to a lurking variable.

Answers

Answer:

The correlation is most likely a causation

Step-by-step explanation:

Causation

A change in one variable causes a change in another variable

Coincidence

The two variables are not related at all, but correlate by chance.

Lurking variable

A variable that is not measured in the study (i.e. it's a third variable that is neither the explanatory nor the response variable)

As fertilizer directly affects plant growth, then the correlation is most likely a causation

What is the solution given the expression
216^2/3

36
6
108
12

Answers

Answer:

36

Step-by-step explanation:

Noticing that 216 = 6^3 and using (x^a)^b = x^ab

216^2/3 = (6^3)^2/3 = 6^3 times 2/3 = 6^2 = 36

How do I solve this problem?

Answers

Answer:

M. E. = +_2.086

Step-by-step explanation:

How do I solve this problem?

Chris is opening candy store. He is charging $4 for a small box of candy and then $1.25 for each additional box. What is the slope and y-intercept for this situation?

Answers

Answers:

Slope = 1.25

y intercept = 4

Explanation:

The slope is the rate of change. In this case, it's the price of getting an extra box.  

The y intercept is the starting cost assuming that everyone has to get at least one small box of candy.

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