Sum and Difference Identities
Find the value of the expression.
cos(-pi/12)
What would -pi/12 be the sum or difference of?

Answers

Answer 1

Notice that

1/6 - 1/4 = -1/12

Then

cos(-π/12) = cos(π/6 - π/4)

cos(-π/12) = cos(π/6) cos(π/4) + sin(π/6) sin(π/4)

cos(-π/12) = (√3/2) (1/√2) + (1/2) (1/√2)

cos(-π/12) = (√6 + √2)/4


Related Questions

Using the law of cosines, write an algebraic proof to show that the angles in an equilateral triangle must equal 60°. Use "∧" to indicate exponents. For example, type a2 as a∧2. (Hint: Let s be a length of each side and x be the angle measure; then use these variables in the law of cosines.)

Answers

The algebraic proof shows that the angles in an equilateral triangle must equal 60° each

What is trigonometry?

Trigonometry is the branch of mathematics which set up a relationship between the sides and angle of the right-angle triangles.

From the question, we are to use the law of cosines to write an algebraic proof that shows that the angles in an equilateral triangle must equal 60°.

Given any triangle ABC, the measures of angles A, B, and C by the law of cosines are

cos A = (b² + c² - a²)/2bc

cos B= (a² + c²- b²)/2ac

cos C = (a²+ b²- c²)/2ab  

Now, given that the triangle is equilateral, with each of the side lengths equal to s

That is, a = b = c = s

Then, we can write that

cos A = (s² + s² - s²)/(2s×s)

cos A = (s² )/(2s²)

cos A = 1/2

cos A = 0.5

∴ A = cos⁻¹(0.5)

A = 60°

Also

cos B = (s² + s² - s²)/(2s×s)

cos B = (s²)/(2s²)

cos B = 1/2

cos B = 0.5

∴ B = cos⁻¹(0.5)

B = 60°

and

cos C = (s² + s² - s²)/(2s×s)

cos C = (s² )/(2s²)

cos C = 1/2

cos C = 0.5

∴ C = cos⁻¹(0.5)

C = 60°

Thus,

A = 60°, B = 60° and C = 60°

Hence, the algebraic proof above shows that the angles in an equilateral triangle must equal 60° each.

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Mike is working on solving the exponential equation 37x = 12; however, he is not quite sure where to start. Using complete sentences, describe to Mike how to solve this equation.

Use the change of base formula: log base b of y equals log y over log b.

Answers

[tex]~~~~~37^x = 12\\\\\implies \ln\left( 37^x \right) = \ln(12)\\\\\implies x \ln (37) = \ln(12)\\\\\implies x = \dfrac{\ln(12)}{\ln(37)}\\\\\implies x \approx 0.689[/tex]

Find the factor of each ff.
6z²+12z+18​

Answers

Answer:

Step-by-step explanation:

6z² + 12z +1 8​

= 6(z^2 + 2z + 3).

That's it.

Find the standard deviation of the data, 12, 19, 9.

Answers

Answer:

4.19

Step-by-step explanation:

Find the mean:

[tex]\text{Mean}=\frac{12+19+9}{3}=\frac{40}{3}[/tex]

Find the standard deviation:

[tex]\text{Standard Deviation}=\sqrt{\frac{(12-\frac{40}{3})^2+(19-\frac{40}{3})^2+(9-\frac{40}{3})^2}{3}}=\sqrt{\frac{158}{9}}\approx4.19[/tex]

can anyone tell me what points I plot these two at ? ty

Answers

Answer:

Both graphs in 2 separate attachments--placed in order

Hope it helps.

Hello ~

My name is Sxnnysoul, and I will be answering your question today! :D

Let's solve for x ~

⇢ [tex]\sf{x^2 \: + \: y^2 \: = \: 4}[/tex]

⇢  [tex]\sf{Step \: 1: \: Add \: -y^2 \: to \: both \: sides.}[/tex]

⇢  [tex]\sf{x^2 \: + \: y^2 \: + \: -y^2 \: + \: = \: 4 \: + \: -y^2}[/tex]

⇢  [tex]\sf{x^2 \: + \: -y^2 \: + \: 4}[/tex]

⇢  [tex]\sf{Step \: 2: \: Take \: square \: root.}[/tex]

⇢  [tex]\sf{x \: = \sqrt{-y^2 \: + \: 4} \: or \: = - \sqrt{-y^2 \: + \: 4}[/tex]

P.S here's the graph that might help you!

Let's solve of x ~

⇢  [tex]\sf{x^2 \: + \: y^2 \: = \: 32}[/tex]

⇢  [tex]\sf{Step \: 1: \: Add \: -y^2 \: to \: both \: sides.}[/tex]

⇢  [tex]\sf{x^2 \: + \: y^2 \: + \: -y^2 \: + \: = \: 32 \: + \: -y^2}[/tex]

⇢  [tex]\sf{x^2 \: + \: -y^2 \: + \: 32}[/tex]

⇢  [tex]\sf{Step \: 2: \: Take \: square \: root.}[/tex]

⇢  [tex]\sf{x \: = \sqrt{-y^2 \: + \: 32} \: or \: x \: = - \sqrt{-y^2 \: + \: 32}[/tex]

P.S here's the second image of the graph. so, you won't get confused.

Hope It Helps! ~

~ Learn With Sxnnysoul ~

[tex]\underline{Answer :}[/tex]

ꜱ x ɴ ɴ ʏ ꜱ ᴏ ᴜ ʟ

This window is designed in the shape of a right trapezoid.

Answers

Answer: 128°

Step-by-step explanation:

   There are 360° in a trapezoid. Since this is a right trapezoid, two of those angles will be equal to 90°. We will set up the following equation, and solve.

360° = 90° + 90° + 52° + x°

360° = 90° + 90° + 52° + x°

360° = 232° + x°

128° = x

x = 128°

   The obtuse angle has a measure of 128°.

Simplify: (5 + i)(5 − i)
A) −12
B) 24i
C) 26
D) 8i

Answers

Answer:

C) 26

Simplify using the FOIL method--used to multiply binomials--and then combine real and imaginary parts of the problem.

5 × 5 = 25 + positive 1(i) = 26

Answer:

option c, 26

Step-by-step explanation:

(5 + i)(5 - i)

Apply complex arithmetic rule: (a + bi)(a - bi) = a^2 + b^2

a = 5, b =1

(5)^2 + (1)^2

(5)^2 = 25

(1)^2 = 1

25 + 1

If 5 times a certain number is 40, and 9 times the same number is 72, how would you find 59 times that number? A)400 + 72 B)40 + 72 C)40 × 72 D)400 + 720 pls tell answer urgently.​

Answers

Answer:

A) 400 + 72

Step-by-step explanation:

Let the certain number be denoted by x.

⇒ 5x = 40 [Equation 1]

⇒ 9x = 72 [Equation 2]

Multiply Equation 1 by 10 :

⇒ 10(5x) = 40(10)

⇒ 50x = 400 [Equation 3]

Finding the sum of Equation 2 and Equation 3 :

⇒ 50x + 9x = 400 + 72

⇒ 59x = 400 + 72

Hence, 59 times a certain number is represented by : 400 + 72

May I please get help to this question.

Answers

Answer: 3

Step-by-step explanation:

Help me with the 2 problems

Answers

Answer:

9) Vincent will not get the correct answer because the + 484 is unneccesary, as he already subtracted it.

10a) 310,000 + x = 465,000; so x = 155,000

10b) 930,000/310,000 = 3 times more

Step-by-step explanation:

Complete the long division problem on your own sheet of paper. Then, fill in the digits. 2 ÷ 694

Answers

Answer:

Here!! Hope i helped.

PLeaseeeee Help

6. Given the order pairs (2, 3), (4, 5), (4, 7), (5, 10), and (6, 8) find the following. Round all final answers to three decimals places. Be careful not the round to early.


Express the line of best fit in the form of y = mx+b.


(a) The line of best fit. =


(b) Find the coefficient of linear correlation. =

Answers

Answer:

B

Step-by-step explanation:

answer is based on results from the Cartesian plane

can anyone help plssss??

Answers

Answer:

42 degrees

Step-by-step explanation:

48+90=138

180-138=42

Find (a) PQ to the nearest tenth and (b) the coordinates of the midpoint of PQ. P(1,4), Q(3,-2)​

Answers

Answer:

a) 6.3; b) (2;1).

Step-by-step explanation:

[tex]a) \ |PQ|=\sqrt{(X_P-X_Q)^2+(Y_P-Y_Q)^2}=\sqrt{4+36}=\sqrt{40} =6.3;[/tex]

[tex]b) \ (\frac{X_P+X_Q}{2};\frac{Y_P+Y_Q}{2}); \ = > \ (2;1).[/tex]

On a recent survey, 35% of those surveyed indicated that they preferred running. If 540 people were surveyed, how many people preferred running?

Answers

Answer: 189 people preferred running.

Step-by-step explanation: 35% is equal to 35/100. Since 540 people were surveyed, we can multiply 35/100 by 540 to find that 189 people out of 540 preferred running. Hope this helps!

Select the correct answer.
Consider this quadratic equation.
X^2+ 1 = 2x-3
Which expression correctly sets up the quadratic formula?

OA. -(-2) + 2)2 - 4(1)(4)
2(1)
OB.-(-2) + VE-2)2 – (1)(4)
2(2)
OC -2 + (-2)2 - 4(1)(4)
2(1)
OD. -2 + (2)2 – 4(1)(-2)
2(1)

Answers

Answer:A.   [tex]\displaystyle{\frac{-(-2) \pm \sqrt{(2)^{2}-4(1)(4)}}{2(1)} }[/tex]

Find the values a, b, and c to substitute into the quadratic formula.

Remember:Standard form

Notice how there are a, b, and c. Everything is left of the equal sign, leaving 0 on the right.

ax² + bx + c = 0

Quadratic formula

Notice how there are a, b, and c too, just like in standard form. After we find standard form, we can substitute a, b and c values into the quadratic formula.

[tex]\displaystyle{x=\frac{-b \pm \sqrt{b^{2}-4ac}}{2a} }[/tex]

Step-by-step solution

Here are the steps we will follow:

Rearrange the equation from the question into standard form.Determine the values for a, b, and c.Substitute a, b, and c into the quadratic formula.Compare options and simplify as needed.

Rearrange into standard form

Move everything to the left while keeping both sides equal.

x² + 1 = 2x – 3                 Equation from the question

x² + 1 + 3 = 2x – 3 + 3     Add three to both sides.

x² + 1 + 3 = 2x                 -3 + 3 cancels out to 0.

x² + 4 = 2x                      Simplify.

x² + 4 – 2x = 2x – 2x     Subtract 2x from both sides.

x² + 4 – 2x = 0                No numbers on the right side is the same as 0.

x² – 2x + 4 = 0                Rearrange to follow ax² + bx + c = 0.

Determine a, b, and c values

Find a, b, and c from standard form.

ax² + bx + c = 0         Standard form

x² – 2x + 4 = 0           No number attached to x² means a = 1.

a = 1,  b = –2,  and  c = 4

Substitute into the quadratic formula

Substitute a = 1, b = –2, and c = 4 into the quadratic formula.

[tex]\displaystyle{x=\frac{-b \pm \sqrt{b^{2}-4ac}}{2a} }[/tex]    

Here is how our formula set up should look:

[tex]\displaystyle{x=\frac{-(-2) \pm \sqrt{(-2)^{2}-4(1)(4)}}{2(1)} }[/tex]

Compare answer options

Let's compare formula set up to the options in the question.

The denominator is 2(1). So, the answer is not option B.

Inside the square root, it says –4(1)(4). So, the answer is not option D.

This leaves us with either option A or option C.

Simplify

Before the ±, it says –(–2). When simplified, –(–2) is 2.

Option C has –2. So, the answer is not option C.

Inside the square root, it says (–2)², which is equal to 2².

When solving exponents of negative numbers,

an odd exponent results in a negative product, and;an even exponent results in a positive product.

The exponent 2 is even.

(–2)² = 4

∵ (–2)² = 4 and 2² = 4

∴ (–2)² = 2²

(–2)² is the same as 2².

Therefore, the answer is option A.

Rahul drives 10 miles in 20 minutes. If he drove three hours in total at the same rate, how far did he go?
Before you try that problem, answer the question below.
How many minutes did Rahul drive in total?

Answers

Answer: 180 minutes

90 miles in 3 hours

Step-by-step explanation:

60 minutes = 1 hour

60 mins/20 mins = 3

60*3 = 180

30 miles per hour for 3 hours is 90 miles

City A is 300 km due east of city B. City C is 200 km on a bearing of 123° from city B. How far is it from C to A?​

Answers

Answer:

500 km

Step-by-step explanation:

300 plus 200 is 500km this is how far it is

The distance between City A & City C is approximately 171.3km

Given that, city A is 300 km due east of city B.

City C is 200 km on a bearing of 123° from city B.

We need to find the distance between the cities A and C,

Here we will use the concept of Cosine rule,

{Refer to the figure attached}

From ∆ABC, to find |AC|,

The cosine rule will be used.

|AC|² = |BC|² + |AB|² - 2(|BC|)(|AB|)cosB

Let |AC| = x

x² = 200² + 300² - 2(200)(300)cos33

x² = 40000 + 90000 - 120000cos33

x² = 130000-100644

x² = 29356

x = √29356

x = 171.3359

x ≈ 171.3km

Therefore, the distance between City A & City C is approximately 171.3km

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1/5 is 60% of what number

Answers

1/5 = 60/100 * x

1/5 * 100/60 = x

100/300 = x

1/3 = x

Answer:

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

Step-by-step explanation:

According to what we know, one-fifth is 60% of a number. Let us call that unknown number x. Since

[tex] \frac{1}{5} = 60\% \: \\ then \\ x = 100\%[/tex]

60% as a fraction is 6/10 or 3/5, in that case 100% as a fraction would be 5/5.

Recall: 60% = 3/5 and 100% = 5/5

therefore:

1/5 = 3/5

x = 5/5

note in order to find the value of x we cross multiply*

[tex] \frac{1}{5} ( \frac{5}{5}) = \frac{3}{5} x[/tex]

[tex] \frac{1}{5} = \frac{3}{5} x \\ \\ \frac{ \frac{1}{5} }{ \frac{3}{5} } = \frac{ \frac{3}{5} }{ \frac{3}{5} } x \\ \\ \frac{1}{5} \times \frac{5}{3} = x[/tex]

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

Find the amount accumulated after investing m principal P for t and an internet rate compounded annually P=40500 r=3.8% t=20 k=12

Answers

The amount of money accumulated after investing the given amount of money at the given rate and time period is $85389.

What is an interest in banking?

Interest is simply the amount of money a lender or financial institution receives for lending out money or pays for receiving money.

The formula for calculating compound interest is expressed as;

A = P(1 + r/k)^(k*t)

Where A is final amount, P is initial principal balance, r is interest rate, k is  number of times interest applied per time period and t is number of time periods elapsed.

Given that;

Initial principal balance P = $40500Interest rate r = 3.8= 3.8/100 = 0.038Time t = 20 yearsNumber of times interest applied per time period = 12 (annually) = 12/12 = 1 Amount accumulated A = ?

A = P(1 + r/k)^(k*t)

A = 40500(1 + 0.038/1)¹ˣ²⁰

A = 40500 × (1.038)²⁰

A = 40500 × 2.10837

A = $85389

Therefore, the amount of money accumulated after investing the given amount of money at the given rate and time period is $85389.

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Given: 1 = 2

If AB = 10, AC = 6, and BC = 6, find AD:

Answers

The length of AD in triangle ABC in which ∠1 = ∠2 is 3.75.

What is Angle Bisector?

The (interior) bisector of an angle, also called the internal angle bisector, is the line or line segment that divides the angle into two equal parts.

Here, Let the lenght of AD be x

         AB = 10 , AC = 6 and BC = 6

by Angle-Bisector theorem which states that

if a ray bisects an angle of a triangle, then it divides the opposite side into segments that are proportional to the other two sides.

So, CD/BD =AC/AB

      CD/(BC-CD) = 6/10

       10. CD = 6.BC - 6.CD

        16 CD = 6 X 6

         16 CD = 36

          CD = 36/16

         CD  = 2.25

Now, AD = AC - CD

         AD = 6 - 2.25

         AD = 3.75

Thus, the length of AD in triangle ABC in which ∠1 = ∠2 is 3.75.

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Solve for x. Round to the nearest tenth.​

Answers

Answer:

x = 27.19

Step-by-step explanation:

Sin(54) =22/x

0.81=22/x

x0.81= 22

x = 27.19


X is equivalent to 27.2

Sin54= 22/x

Which of these numbers are relatively prime to 51? Select all that apply. da) 84 Ob) 70 Oc) 62 0d) 30

Answers

Answer:

  b) 70

  c) 62

Step-by-step explanation:

Numbers are relatively prime when they have no factors in common.

__

The factors of 51 are ...

  51 = 3×17

The factors of the other numbers are ...

  84 = 2²×3×7 . . . . . has a factor of 3 in common with 51

  70 = 2×5×7 . . . . . . no factors in common

  62 = 2×31 . . . . . . . no factors in common

  30 = 2×3×5 . . . . . has a factor of 3 in common with 51

The numbers 70 and 62 are relatively prime to 51.

Given the function f(x) = (1/4)^x , how will g(x) = (1/4) ^x-3 + 5 be translated

Answers

See

x is decreased by 3 .

and y is increased by 5

So translation is

f(x)=(1/4)^x

Hence

f(x)=(1/4)^x-3+5

So

x will go 3 units right

y will go 5units up

Graph attached

Answer:

Translations

For [tex]a > 0[/tex]

[tex]f(x+a) \implies f(x) \: \textsf{translated}\:a\:\textsf{units left}[/tex]

[tex]f(x-a) \implies f(x) \: \textsf{translated}\:a\:\textsf{units right}[/tex]

[tex]f(x)+a \implies f(x) \: \textsf{translated}\:a\:\textsf{units up}[/tex]

[tex]f(x)-a \implies f(x) \: \textsf{translated}\:a\:\textsf{units down}[/tex]

Parent function:

[tex]f(x)=\left(\dfrac{1}{4}\right)^x[/tex]

Translated 3 units to the right:

[tex]f(x-3)=\left(\dfrac{1}{4}\right)^{x-3}[/tex]

Translated 5 units up:

[tex]f(x-3)+5=\left(\dfrac{1}{4}\right)^{x-3}+5[/tex]

[tex]\implies g(x)=f(x-3)+5[/tex]

Therefore:

[tex]\textsf{g(x) is a translation of f(x) by }\left(\begin{array}{c}3\\5\\\end{array}\right)[/tex]

PLEASE HELP For what value of x is the parallelogram a rectangle. The arrows point to the entire diagonal, not just a segment.

Answers

Step-by-step explanation below

Need help thank you

Answers

Answer: [tex]i\sqrt{5}[/tex]

Step-by-step explanation:

[tex]\sqrt{-5}=\sqrt{(-1)(5)}=\sqrt{-1} \sqrt{5}=\boxed{i\sqrt{5}}[/tex]

Sandy baked two dozen cookies. She gave ten cookies to the neighbours and ate three cookies.
How many cookies are left?

Answers

Answer:

11

Step-by-step explanation:

2 dozen = 24

24-10=14

14-3=11

Answer:

11

Step-by-step explanation:

two dozens is 24 because one dozen is 12. 24-10=14-3=11

PLEASE HELP WILL MARK BRSINLIEST!!!!!pleaseeee

Answers

Your answer will be 3x^2-7x.

Answer:

[tex]x(3x-7)=3x^2-7x[/tex]

Step-by-step explanation:

[tex]\Large \begin{array}{| c | c | c |}\cline{1-3} \textsf{x} & 3x & -7\\\cline{1-3} x & 3x^2 & -7x\\\cline{1-3}\end{array}[/tex]

[tex]\textsf{Therefore,}\quad x(3x-7)=3x^2-7x[/tex]

As a single logarithm, 2log2 6- log29+ 1/3log2 27 = log2 12.

Answers

Answer:

true

Step-by-step explanation:

2log2 6- log2 9+ 1/3log2 27 =

= log2 6² - log2 9 + log2 27^(1/3)

= log2 36 - log2 9 + log2 3

= log2 [(36 × 3)/9]

= log2 12

The statement is true.

is 3/2 = to square of 2

Answers

Answer:

No, it will not

Step-by-step explanation:

as square of 2 is 4

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