find the exact value of 6cos(105°)​

Answers

Answer 1

Answer:

[tex]-\frac{3(\sqrt{6}-\sqrt{2})}{2}\text{ or } \frac{-3\sqrt{6}+3\sqrt{2}}{2}}\text{ or }\frac{3(\sqrt{2}-\sqrt{6})}{2}[/tex]

Step-by-step explanation:

There are multiple ways to achieve and even express the exact answer to this problem. Because the exact value of [tex]6\cos(105^{\circ}})[/tex] is a non-terminating (never-ending) decimal, it does not have a finite number of digits. Therefore, you cannot express it as an exact value as a decimal, as you'd either have to round or truncate.

Solution 1 (Cosine Addition Identity):

Nonetheless, to find the exact value we must use trigonometry identities.

Identity used:

[tex]\cos(\alpha +\beta)=\cos \alpha \cos \beta-\sin \alpha \sin \beta[/tex]

Notice that [tex]45+60=105[/tex] and therefore we can easily solve this problem if we know values of [tex]\cos(45^{\circ})[/tex], [tex]\cos(60^{\circ})[/tex], [tex]\sin (45^{\circ})[/tex], and [tex]\sin(60^{\circ})[/tex], which is plausible as they are all key angles on the unit circle.

Recall from either memory or the unit circle that:

[tex]\cos(45^{\circ})=\sin(45^{\circ})=\frac{\sqrt{2}}{2}[/tex] [tex]\cos(60^{\circ})=\frac{1}{2}[/tex] [tex]\sin(60^{\circ})=\frac{\sqrt{3}}{2}[/tex]

Therefore, we have:

[tex]\cos(105^{\circ})=\cos(45^{\circ}+60^{\circ}}),\\\cos(45^{\circ}+60^{\circ}})=\cos 45^{\circ}\cos 60^{\circ}-\sin 45^{\circ}\sin 60^{\circ},\\\cos(45^{\circ}+60^{\circ}})=\frac{\sqrt{2}}{2}\cdot \frac{1}{2}-\frac{\sqrt{2}}{2}\cdot \frac{\sqrt{3}}{2},\\\cos(105^{\circ})=\frac{\sqrt{2}}{4}-\frac{\sqrt{6}}{4},\\\cos(105^{\circ})={\frac{-\sqrt{6}+\sqrt{2}}{4}}[/tex]

Since we want the value of [tex]6\cos 105^{\circ}[/tex], simply multiply this by 6 to get your final answer:

[tex]6\cdot {\frac{-\sqrt{6}+\sqrt{2}}{4}}=\frac{-3\sqrt{6}+3\sqrt{2}}{2}}=\boxed{\frac{3(\sqrt{2}-\sqrt{6})}{2}}[/tex]

Solution 2 (Combination of trig. identities):

Although less plausible, you may have the following memorized:

[tex]\sin 15^{\circ}=\cos75^{\circ}=\frac{\sqrt{6}-\sqrt{2}}{4},\\\sin 75^{\circ}=\cos15^{\circ}=\frac{\sqrt{6}+\sqrt{2}}{4}[/tex]

If so, we can use the following trig. identity:

[tex]\cos(\theta)=\sin(90^{\circ}-\theta)[/tex] (the cosine of angle theta is equal to the sine of the supplement of angle theta - the converse is also true)

Therefore,

[tex]\cos (105^{\circ})=\sin (90^{\circ}-105^{\circ})=\sin(-15^{\circ})[/tex]

Recall another trig. identity:

[tex]\sin(-\theta)=-\sin (\theta)[/tex] and therefore:

[tex]\sin (-15^{\circ})=-\sin (15^{\circ})[/tex]

Multiply by 6 to get:

[tex]6\cos (105^{\circ})=-6\sin (15^{\circ})=-6\cdot \frac{\sqrt{6}-\sqrt{2}}{4}=\boxed{-\frac{3(\sqrt{6}-\sqrt{2})}{2}}[/tex] (alternative final answer).


Related Questions

PRACTICE
Find and circle the verb to be in the text about
Sean Canty.
2 a Practice the verb to be.
5 b
2. We are
1.1
.... at home.
in the classroom.
3. My father ............. at work now.
4. My grandmother ....... alive.
5. It ............. Saturday today.
1. What
2
-
3. Whe
4. How
5. Wha
2h

Answers

jvdhvfggvvvbbbbbbbbb

The explicit rule for a sequence and one of the specific terms is given. Find the position of the given term.

f(n) = 3.75n − 27.5; 25


Step 1 out of 2:
You know that the value of f(n) is 25. Substitute 25 for f(n) in f(n) = 3.75n − 27.5.
25 = 3.75n − 27.5
= 3.75n

Answers

Answer:

14

Step-by-step explanation:

Given :

f(n) = 3.75n − 27.5

f(n) = 25

Put f(n) = 25 in the equation :

25 = 3.75n - 27.5

25 + 27.5 = 3.75n

52.5 = 3.75n

52.5 / 3 75 = n

14 = n

The position of the term is 14

Find the Taylor series for f(x) centered at the given value of a. (Assume that f has a power series expansion. Do not show that Rn(x)→0 . f(x)=lnx, a=

Answers

Answer:

Here we just want to find the Taylor series for f(x) = ln(x), centered at the value of a (which we do not know).

Remember that the general Taylor expansion is:

[tex]f(x) = f(a) + f'(a)*(x - a) + \frac{1}{2!}*f''(a)(x -a)^2 + ...[/tex]

for our function we have:

f'(x) =  1/x

f''(x) = -1/x^2

f'''(x) =  (1/2)*(1/x^3)

this is enough, now just let's write the series:

[tex]f(x) = ln(a) + \frac{1}{a} *(x - a) - \frac{1}{2!} *\frac{1}{a^2} *(x - a)^2 + \frac{1}{3!} *\frac{1}{2*a^3} *(x - a)^3 + ....[/tex]

This is the Taylor series to 3rd degree, you just need to change the value of a for the required value.

Solve the two step equations
1. -3x - 4 = 23
2. x/2 - 12 = -4
3. 6a + ( -1) = 10
4. - ( x + 2 ) = 12
5. 7a + 12 = 10
6. -4 ( a + 2 ) = 12

Answers

Hello!

1) -3x - 4 = 23

-3x = 23 + 4

-3x = 27

x = 27 : (-3)

x = -9

2) x/2 - 12 = -4

x - 24 = -8

x = -8 + 24

x = 16

3) 6a + (-1) = 10

6a - 1 = 10

6a = 10 + 1

6a = 11

a = 11 : 6

a = 11/6

4) -(x + 2) = 12

x + 2 = -12

x = -12 - 2

x = -14

5) 7a + 12 = 10

7a = 10 - 12

7a = -2

a = -2 : 7

a = -2/7

6) -4(a + 2) = 12

a + 2 = -3

a = -3 - 2

a = -5

Good luck! :)

una fuerza constante F de magnitud igual a 3lb se aplica al bloque que se muestra en la figura. F tiene la misma dirección que el vector a= 3i + 4j. determine el trabajo realizado en la dirección de movimiento si el bloque se mueve de P1 (3, 1) a P2 (9, 3). Suponga que la distancia se mide en pies.

Answers

Uh is that Spanish? Bc I can’t speak Spanish

A hypothesis will be used to test that a population mean equals 5 against the alternative that the population mean is less than 5 with known variance σ. What is the critical value for the test statistic for the significance level of 0.010

Answers

Answer:

The critical value is [tex]Z_c = -2.327[/tex]

Step-by-step explanation:

A hypothesis will be used to test that a population mean equals 5 against the alternative that the population mean is less than 5

Test if the mean is less than a value, so a one-tailed hypothesis test is used.

Known variance σ.

This means that the z-distribution is used to solve this question.

What is the critical value for the test statistic for the significance level of 0.010?

Z with a p-value of 0.01, so, looking at the z-table, [tex]Z_c = -2.327[/tex]

1 point
Use log10 3-0.4771; log10 5 0.699010810 7 0.8451; log10 11 1.0414 to approximate the value of each expression-
log10 14710910 (147)

Answers

Answer:

[tex]\log_{10}(147) = 2.1673[/tex]

Step-by-step explanation:

Given

[tex]\log_{10} 3 = 0.4771[/tex]

[tex]\log_{10} 5 = 0.6990[/tex]

[tex]\log_{10} 7= 0.8451[/tex]

[tex]\log_{10} 11 = 1.0414[/tex]

Required

Evaluate [tex]\log_{10}(147)[/tex]

Expand

[tex]\log_{10}(147) = \log_{10}(49 * 3)[/tex]

Further expand

[tex]\log_{10}(147) = \log_{10}(7 * 7 * 3)[/tex]

Apply product rule of logarithm

[tex]\log_{10}(147) = \log_{10}(7) + \log_{10}(7) + \log_{10}(3)[/tex]

Substitute values for log(7) and log(3)

[tex]\log_{10}(147) = 0.8451 + 0.8451 + 0.4771[/tex]

[tex]\log_{10}(147) = 2.1673[/tex]

What is the value of x

Answers

Answer:

[tex]6x+3+69=180[/tex]

[tex]6x=180-72[/tex]

[tex]6x=108[/tex]

[tex]x=18[/tex]

--------------------------

hope it helps..

have a great day!!

Jamal opens a savings account with a starting balance of $200 and plans to
deposit $75 each week after opening the account. His savings over time is
represented by the graph below. How would this graph change if Jamal
decided to deposit $100 each week instead?

Answers

the graph would steeper, meaning more savings over time

(3x^3)^2 write without exponent

Answers

Answer:

9*x*x*x*x*x*x.

Step-by-step explanation:

(3x^3)^2

= 3^2 * x^(3*2)

= 3^2 * x^6

= 9*x*x*x*x*x*x

What is 75% as a fraction

Answers

Answer:

[tex]\frac{75}{100}[/tex]

Step-by-step explanation:

3/4

75 percent is 3/4 of 100 percent.

is this right? PLEASE HELP ILL MARK

Answers

Answer:

yeah u r correct...

hope it helps ..stay safe healthy and happy.

Identify the domain of the table of values shown

Answers

Answer:

{-6,0,2,4}

Step-by-step explanation:

Can any one you help me with this ?

Answers

NUE is 30° LUN is 60° EUS is 30° LUE is 90° LUS is 120°

Step-by-step explanation:

NUE is given

LUN was from the 90° angle LUE but just minus 30°

EUS is honestly a guess :/

LUE is obviously 90° as we used it earlier

LUS was the 90° plus the EUS

I need help with this problem.

Answers

Answer:

-4

Step-by-step explanation:

2t=-1-7

t=-8/2

t=-4

i am not sure also

Question 4 of 10
Is the graph increasing, decreasing, or constant?
O A. Decreasing
O B. Constant
O C. Increasing

Answers

The graph shown is decreasing.

Assume the population is bell-shaped. Between what two values will approximately 95% of the population be

Answers

Answer:The 95% Rule states that approximately 95% of observations fall within two ... about 95% will be within two standard deviations of the mean, and about 99.7% will be ... Suppose the pulse rates of 200 college men are bell-shaped with a mean of 72 ... 1.2 - Samples & Populations ... 3.5 - Relations between Multiple Variables.

Step-by-step explanation:

On weekend nights, a large urban hospital has an average of 4.8 emergency arrivals per hour. Let X be the number of arrivals per hour on a weekend night at this hospital. Assume that successive arrivals are random and independent. What is the probability P(X < 3)?

Answers

Answer:

P(X < 3) = 0.14254

Step-by-step explanation:

We have only the mean, which means that the Poisson distribution is used to solve this question.

Poisson distribution:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]

In which

x is the number of sucesses

e = 2.71828 is the Euler number

[tex]\mu[/tex] is the mean in the given interval.

On weekend nights, a large urban hospital has an average of 4.8 emergency arrivals per hour.

This means that [tex]\mu = 4.8[/tex]

What is the probability P(X < 3)?

[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]

So

[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]

[tex]P(X = 0) = \frac{e^{-4.8}*4.8^{0}}{(0)!} = 0.00823[/tex]

[tex]P(X = 1) = \frac{e^{-4.8}*4.8^{1}}{(1)!} = 0.03950[/tex]

[tex]P(X = 2) = \frac{e^{-4.8}*4.8^{2}}{(2)!} = 0.09481[/tex]

So

[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.00823 + 0.03950 + 0.09481 = 0.14254[/tex]

P(X < 3) = 0.14254

Maya has already run 1 mile on her own, and she expects to run 1 mile during each track practice. How many miles would Maya have run after 48 track practices?

Answers

Answer:

Step-by-step explanation:

48+1=49

Which statement about y=x^2-12x+35 is true?
A. The zeros are 7 and 5, because y=(x-7)(x-5)
B. The zeros are 7 and -5, because y=(x+7)(x-5)
c. The zeros are -7 and -5, because y=(x+7)(x+5)
D. The zeros are -7 and -5, because y=(x-7)(x-5)

Answers

Answer:The zeros are 7 and 5, because y=(x-7)(x-5)

Step-by-step explanation:

A rectangular vegetable garden will have a width that is 3 feet less than the length, and an area of 54square feet. If x represents the length, then the length can be found by solving the equation: x(x-3)=54 What is the length, x, of the garden? The length is blank feet.

Answers

Answer: 9 feet

Step-by-step explanation:

From the information given, we have already been given the equation which is x(x-3)=54. Therefore we will find the value of x which will be:

x(x-3)=54

x² - 3x - 54

x² - 9x + 6x - 54

x(x - 9) + 6(x - 9)

Therefore,

(x - 9) = 0

x = 0 + 9

x = 9

The length is 9 feet

The width will be:

x - 3 = 9 - 3 = 6 feet

John's age 4 years ago, if he will be y years old in 5 years

Answers

9514 1404 393

Answer:

  y -9

Step-by-step explanation:

From 4 years ago until 5 years from now, John will age 9 years. That is, his age 4 years ago is 9 years less than it will be in 5 years.

John's age 4 years ago is y-9 years.

Gloria received a 4 percent raise and is now making $24,960 a year, what was her salary before the raise?

Answers

She gets a 4% raise so her new pay is 100% + 4% of her previous pay.

104% = 1.04 as a decimal.

Divide her new pay by 1.04:

24,960 / 1.04 = 24,000

Her previous pay was $24,000

Find the value of x pls help

Answers

9514 1404 393

Answer:

  x = 36°

Step-by-step explanation:

The exterior angle is equal to the sum of the remote interior angles. A linear pair is supplementary. So, you can find x either of two ways:

  2x = x + (180 -4x)   ⇒   5x = 180   ⇒   x = 36

Or ..

  4x = x + (180 -2x)   ⇒   5x = 180   ⇒   x = 36

The value of x is 36°.

1. In the spring of 2017, the Consumer Reports National Research Center conducted a survey of 1007 adults to learn about their major health-care concerns. The survey results showed that 574 of the respondents lack confidence they will be able to afford health insurance in the future. Develop a 90% confidence interval for the population proportion of adults who lack confidence they will be able to afford health insurance in the future.

Answers

Answer:

The correct answer is "1668". A further solution is provided below.

Step-by-step explanation:

According to the question,

Estimated proportion,

[tex]\hat{p} = \frac{574}{1007}[/tex]

  [tex]=0.57[/tex]

Margin of error,

E = 0.02

Level of confidence,

= 90%

= 0.90

Critical value,

[tex]Z_{0.10}=1.65[/tex]

Now,

⇒  [tex]0.02=1.65\times \sqrt{\frac{0.57\times 0.43}{n} }[/tex]

 [tex]0.0004=2.7225\times \frac{0.2451}{n}[/tex]

         [tex]n=\frac{2.7225\times 0.2451}{0.0004}[/tex]

             [tex]=1668.21[/tex]

or,

         [tex]n \simeq 1668[/tex]

2/9 divided by 5/6
help pleaseee​

Answers

Hey there!

[tex]\mathsf{\dfrac{2}{9}\div\dfrac{5}{6}}[/tex]

[tex]\mathsf{= \dfrac{2\times6}{9\times5}}[/tex]

[tex]\mathsf{2\times 6 = \bf 12}[/tex]

[tex]\mathsf{9\times5 = \bf 45}[/tex]

[tex]\boxed{\mathsf{=\bf \dfrac{12}{45}}}[/tex]

[tex]\large\textsf{BOTH NUMBERS has the Greatest Common Factor (GCF) of 3}[/tex]

[tex]\mathsf{= \dfrac{12\div3}{45\div3}}[/tex]

[tex]\mathsf{12\div3=\bf 4}[/tex]

[tex]\mathsf{45\div3=\bf 15}[/tex]

[tex]\boxed{\mathsf{=\bf \dfrac{4}{15}}}[/tex]

[tex]\boxed{\boxed{\large\textsf{Answer: }\mathsf{\bf \dfrac{4}{15}}}}\huge\checkmark[/tex]

[tex]\large\textsf{Good luck on your assignment and enjoy your day!}\\\\\\~\frak{Amphitrite1040:)}}[/tex]

A statistics professor plans classes so carefully that the lengths of her classes are uniformly distributed between 47.0 and 57.0 minutes. Find the probability that a given class period runs between 51.25 and 51.5 minutes.

Answers

Answer:

0.025 = 2.5% probability that a given class period runs between 51.25 and 51.5 minutes.

Step-by-step explanation:

Uniform probability distribution:

An uniform distribution has two bounds, a and b.

The probability of finding a value between c and d is:

[tex]P(c \leq X \leq d) = \frac{d - c}{b - a}[/tex]

Uniformly distributed between 47.0 and 57.0 minutes.

This means that [tex]a = 47, b = 57[/tex]

Find the probability that a given class period runs between 51.25 and 51.5 minutes.

[tex]P(c \leq X \leq d) = \frac{51.5 - 51.25}{57 - 47} = 0.025[/tex]

0.025 = 2.5% probability that a given class period runs between 51.25 and 51.5 minutes.

There are 92 students enrolled in an French course and 248 students enrolled in a Spanish course. Construct a ratio comparing students enrolled in a French course to students enrolled in a Spanish course. Write your answer as a decimal, rounded to the thousandths place.

Answers

Answer:

0.371

Step-by-step explanation:

The ratio comparing students enrolled in a French course to students enrolled in a Spanish course rounded to the thousandths place is 0.371.

What is the ratio?

A ratio indicates how many times one number contains another. If a and b are to objects then ratio of a to the b is given as a : b.

Now it is given that,

Students enrolled in a French course = 92

Students enrolled in a Spanish course = 248

So, Ratio comparing students enrolled in a French course to students enrolled in a Spanish = Students enrolled in a French course / Students enrolled in a Spanish course

Ratio comparing students enrolled in a French course to students enrolled in a Spanish = 92/248

Ratio comparing students enrolled in a French course to students enrolled in a Spanish = 0.370967

To rounded to the thousandths place, the digit at the thousandth place is 0 and right to it is 9 which is greater than 5 so round up the place value at thousandths place.

Ratio comparing students enrolled in a French course to students enrolled in a Spanish = 0.371

Thus, the ratio comparing students enrolled in a French course to students enrolled in a Spanish course rounded to the thousandths place is 0.371.

To learn more about ratio:

https://brainly.com/question/1504221

#SPJ2

need help now!!! Please and thanks ​

Answers

Answer:

the answer of r is 8 i hope it will help

A photograph has a length that is inches longer than its width, x. So its area is given by the expression square inches. If the area of the photograph is square inches, what is the width of the photograph?

The width of the photograph is blank inches.

Answers

Answer:

width is also "inches"

Step-by-step explanation:

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