Use a Double- or Half-Angle Formula to solve the equation in the interval [0, 2π). (Enter your answers as a comma-separated list.)
2 sin2(θ) = 2 + cos(2θ)
θ=

Use a Double- or Half-Angle Formula to solve the equation in the interval [0, 2π). (Enter your answers as a comma-separated list.)
cos(2θ) + 7 cos(θ) = 8
θ=

Answers

Answer 1

For the first equation, recall that sin²(θ) = (1 - cos(2θ))/2. Then

2 sin²(θ) = 2 + cos(2θ)

1 - cos(2θ) = 2 + cos(2θ)

2 cos(2θ) = -1

cos(2θ) = -1/2

2θ = arccos(-1/2) + 2   or   2θ = 2π - arccos(-1/2) + 2

(where n is any integer)

2θ = 2π/3 + 2   or   2θ = 4π/3 + 2

θ = π/3 +   or   θ = 2π/3 +

In the interval [0, 2π), the solutions are θ = π/3, 2π/3, 4π/3, 5π/3.

For the second equation, rearrange the previous identity to arrive at

cos(2θ) = 1 - 2 sin²(θ) = 2 cos²(θ) - 1

Then

cos(2θ) + 7 cos(θ) = 8

2 cos²(θ) - 1 + 7 cos(θ) = 8

2 cos²(θ) + 7 cos(θ) - 9 = 0

(2 cos(θ) + 9) (cos(θ) - 1) = 0

2 cos(θ) + 9 = 0   or   cos(θ) - 1 = 0

cos(θ) = -9/2   or   cos(θ) = 1

Since |-9/2| > 1, and cos(θ) is bounded between -1 and 1, the first case offers no solutions. This leaves us with

cos(θ) = 1

θ = arccos(1) + 2

θ = 2

so that there is only one solution in [0, 2π), θ = 0.


Related Questions

Determine whether (a) x = -1 or (b) x = 2 is a solution to this equation

Answers

Answer:

x = 2 is the solution to x + 1.5 = 3.5

Step-by-step explanation:

x + 1.5 = 3.5

   -1.5      -1.5

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

x = 2

Suppose an average student can answer 6 homework questions in 30 minutes. If X follows an exponential distribution and measures the length of time between starting two homework questions. What is the value of μ?

Answers

Answer:

10

Step-by-step explanation:

Make a ratio like

6 : 30

2 : x

Then cross multiple

6x = 60

Make x subject formula

x = 10

I hope it helped

How do we solve this?

Answers

It asks for partial derivative, and you have to derive it with respect to 'y' variable.

[tex]f_y(x,y)=\frac{\partial f}{\partial y}=\frac{\partial}{\partial y}( 6x+2y+4)=2[/tex]

Help me please guys thanks

Answers

Answer:

A is correct

Step-by-step explanation:

A refrigerator magnet uses five eights of an inch of magnetic tape how many refrigerator magnets can you make with 10 inches of magnetic tape

Answers

ANSWER: You can make 16 refrigerator magnets.

If you divide 10 by 5/8, you multiply by the reciprocal of 5/8 which is 8/5. You have 8/5 x 10. Cross simplify and you have 16.

i need help and thx you freinds

Answers

Answer:

Below

Step-by-step explanation:

Find the areas of the triangles on the sides

A = bh / 2

   = (3)(5) / 2

   = 7.5

There are 2 of these so it would just be 15

Now for the square

A = lw

   = (5)(6)

   = 30

Add em all up

Total area = 15 + 30

                 = 45 cm^2

Hope this helps!

solve for P assume that none of the denominators are equal to 0
Kl=y(f/p+n + r/u)​

Answers

Step-by-step explanation:

KI=yf/p+n + yr/u

(p+n) KI - yrp/u -yrn/u = yf

pKI - yrp/u = yf - nKI + yrn/u

p(KI - yr/u) = yf - nKI + yrn/u

p = (1/KI-yr/u)(yf-nKI+yrn/u)

2x + 5y = 10 into slope- intercept form

Answers

Answer:

y=-2x+10

Step-by-step explanation

Hope this helped

Look at the image for the question.

Answers

Answer:

38 cm^2

Step-by-step explanation:

The surface area of a rectangular prism is

SA = 2(lw+wh+lh) where h is the height l is the length and w is the width

SA = 2( 3*1 + 3*4+4*1)

    = 2(3+12+4)

   = 2(19)

   = 38 cm^2

(3+4i)^2

(2+4i)(7-8i)

Answers

Answer:

10 (-61 + 102 i)

(3 + 4 i)^2 (2 + 4 i) (7 - 8 i)  

Step-by-step explanation:

(3 + 4 i)^2 (2 + 4 i) (7 - 8 i)

10 (-61 + 102 i)

r = 50 sqrt(565) (radio), θ = π - tan^(-1)(102/61) (ángulo)

50 sqrt(565) (cos(π - tan^(-1)(102/61))+i sin(π - tan^(-1)(102/61)))

50 sqrt(565) e^(i (π - tan^(-1)(102/61)))

x^2 + 1220 x + 1412500

Intro to Translations
Acellus
Find the image of the given point
under the given translation.
P(-1,2)
T(x, y) = (x + 2, y - 4)
P' = ([?], [])
Enter the number that belongs
in the green box.

Answers

Answer:

(1,-2)

Step-by-step explanation:

P(-1,2) and (x, y) -> (x + 2, y - 4). Plugging in x and y in the transformation, the transformed points are (-1+2, 2-4) = (1,-2)

compare the following rational number
[tex] \frac{4}{5} and \frac{7}{5} [/tex]

Answers

Answer:

7/5 is greater than 4/5

Answer:

[tex]\frac{4}{5}[/tex]  <  [tex]\frac{7}{5}[/tex]

if the cost price of 18 cycles is equal to selling price of 16 cycles .find the gain or loss percentage​

Answers

Answer:

Gain%=12.5%

Step-by-step explanation:

I ASSUMED COST PRICE=Rs.100

PLEASE HELP!!! WILL GIVE BRAINLIEST!!!


A package is in the shape of a triangular prism. The bases are right triangles with perpendicular legs measuring 9 centimeters and 12 centimeters. The distance between the bases is 10 centimeters.


What is the surface area of the triangular prism?


210 square centimeters

318 square centimeters

360 square centimeters

468 square centimeters

Answers

Answer:

Step-by-step explanation:

Area of base = 0.5×9×12 = 54 cm²

Hypotenuse of base = √(9²+12²) = 15

Lateral surface area = 10(9+12+15) = 360 cm²

Total surface area = 2×54 + 360 = 468 cm²

in a children of 700 inmates,25% are living with polio and 30% are girls . if 30% og the girls have polio, how many are the boys without polio

Answers

Answer: 378 Boys

Explanation:

Total no. Inmates = 700

Living with polio = 25/100×700

= 175 inmates

Total girls = 30/100×700

= 210 Girls

30% of girls Having polio = 30/100×210

= 63 Girls

Total Boys = 700 - 210

= 490 Boys

Total boys with polio = 175 - 63

= 112 boys

Boys without polio = 490 - 112

= 378 boys

Must click thanks and mark brainliest

Out of a total of 10 college textbooks estimate the standard deviation of their ages if the oldest textbook is known to be 7.9 years old and the newest textbook is 1.3 years old.
A. 0.5 years
B. 1.1 years
C. 2.3 years
D. 2.9 years
E. 3.3 years

Answers

Answer: The answer is D 2.9 years

Step-by-step explanation:

solve for x. please help !

Answers

Answer:

-2

Step-by-step explanation:

3x + 8x - 3 = -25

Move the -3 over to the other side. This will make the -3 into positive 3

3x + 8x = -25 + 3

Now add like terms

11x = -22

Divide both sides by 11 to get x by itself

x = -2

Answer:

x= -2

Step-by-step explanation:

First you combine the like terms 3x and 8x which then gives you 11x

then you'll have 11x-3=-25

add 3 to both sides and you have 11x=-22

divide the 11 on both sides

then you'll have x=-2

Reflect figure E across the x-axis and then reflect across the y-axis. What is the resulting figure?
rectangle D
B
rectangle B
9
rectangle C
10
rectangle A

Answers

Answer:

2nd option, rectangle B

Step-by-step explanation:

After reflexion, the figure will be at the left side of x=-5

If sam runs 63,756 feet in 70 min what's his miles per hour

Answers

Answer:

10.35 miles per hr

Step-by-step explanation:

first convert ft into mi

then calculate the distance traveled in one min

multiply the answer by 60

then you get the answer

the height of a tree is 170m the lower and upper bound of it's height is ​

Answers

9514 1404 393

Answer:

  [165, 175) meters

Step-by-step explanation:

The rule with respect to questions like this is that the bounds are ±1/2 of the place value of the least-significant digit. Here, the integer portion of the number has trailing zeros, and there is no decimal point or fractional part. Ordinarily, this combination of characteristics would signal that the trailing zeros are not significant, so the only significant digits are 1 and 7. The place value of the least significant digit is 10, so the bounds on the measurement are this number ±1/2(10) = ±5.

Of course, 175 rounds up to 180, so the upper bound is a limit, rather than an actual value. The height should be interpreted in this context as ...

  165 m ≤ height < 175 m

The lower and upper bounds are 165 m and 175 m, respectively.

_____

Additional comment

The best way to avoid any ambiguity as to whether trailing zeros are significant is to use scientific notation. If a zero in the ones place is significant, that is conventionally indicated by a decimal point: "170.". If scientific notation is used, the number would be reported as 1.70×10² to indicate the trailing zero is significant.

For reference, Earth's tallest tree is a redwood just under 116 meters high.

Please help me l am in many problem please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please please ​

Answers

Answer:

Answer for g

Step-by-step explanation:

i think its this way because i dont know the question

HELP! What is the probability of randomly picking a green marble from a bag of 10 green marbles, 10 yellow marbles, and 5 red marbles?

Answers

Answer:

2/5

Step-by-step explanation:

For probability, it's the

number of the type you want

_______________________

the total number of items

So the equation for this would be

10/10+10+5

= 10/25

= 2/5

The final answer is 2/5. Keep in mind that probability is a ratio of likeliness between things, so you CANNOT write it as a decimal!

I hope this helped! :D

34 Proportions
Mathematics, Pre-Algebra
Question 2
A boat can travel 21 miles on 7 gallons of gasoline. How far can it travel on 17 gallons?

Answers

Answer:

51 miles

Step-by-step explanation:

hope it's clear and understandable

:)

Please help! Determine whether the conjecture is true or false and put an example on why it is

Answers

Answer:

Step-by-step explanation:

The first one is true. There can't be any other choice.

a = 5959599949 b = 0 then a*b = 0 because b = 0

The Second one is also true, although you may stall trying to figure out what is meant.

Suppose the angle to start with is 30 degrees

There are two angles that are supplementary to this angle. They can only be 180 - 30 = 150 each. Therefore they are equal to each other. This happens because supplementary angles must add to 180 and nothing else.

The third one is false. You can think of states like Montana which has 3 syllables and Wyoming which also has 3. Texas has two. But guess what? Maine only has 1.

The last one is also false. If you square an even number, you get an even number. Add 1 and you get an odd number. 4^2 = 16 Add 1 you get 17. Seventeen is odd.

Need to be in order Smallest to biggest question.

Want to check if my answers are right.

Answers

Answer:

a49%, 1/2,0.55,3/5

b)0.2,1/4,27%,3/10

c)9/10,95%,0.99,97/100

d)30%,1/3,0.6,2/3

e)0.09,10%,11/100,0.125

A lab technician needs 35 ml of 15% base solution for a certain experiment,
but she has only 10% solution and 20% solution. How many milliliters of
the 10% and the 20% solutions should she mix to get what she needs?

Answers

Answer:

17.5ml- of 10 percent solution, 17.5ml- of 20 percent solution

Step-by-step explanation:

35:100*15=5.25- ml of alkali in the base solution

Suppose we need x ml of 10 percents solution and 35-x - of 20 percents.

Then The quantity of alkali in the first one (10 percents) is x/100*10=0.1x

when in the second one we have (35-x)/100*20= 7-0.2x of alkali

0.1x+7-0.2x=5.25

7-0.1x= 5.25

0.1x=1.75

x=17.5- 0f 10 percents

35-17.5=17.5 - of 20 percents

-3/4÷-1/2

pls help armieee​

Answers

Answer:

exact form : 3/2

decimal form 1.5

mixed number form 1 1/2

Which expression describes this graph?

A. x -5
B. x -5
C. x < -5
D. x > -5

Answers

Answer:

C

Step-by-step explanation:

The equation that described the graph is x<-5

Two complementary angles have measures of s and t. if t is less than twice s, which system of linear equations can be used to determine the measure of each angle? Please explain answer. I know s+t=90. But how do you get to t=2s-90

Answers

The required expressions are both equations 1 and 2 as shown:

[tex]s + t = 90 ......... 1[/tex]

[tex]t<2s[/tex] .... 2

Complementary angles are angles that sum up to 90 degrees. For instance, and A and B are complementary if A + B = 90.

According to the question, if two complementary angles have measures of s and t then:

[tex]s + t = 90 ......... 1[/tex]

Twice of 's' is expressed as [tex]2s[/tex]

If t is less than twice s, this can be expressed as [tex]t<2s[/tex] .... 2

The required expressions are both equations 1 and 2 as shown:

[tex]s + t = 90 ......... 1[/tex]

[tex]t<2s[/tex] .... 2

Learn more on word problems leading to simultaneous equations here: https://brainly.com/question/14294864

Which side of the pentagon on the right corresponds to
side KJ on the pentagon on the left.

Answers

Answer:

side st.

Step-by-step explanation:

st corresponds to kj since a it has five sides.

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