Help, Help, Please
[tex] \sf find \: the \: value \: of \: \theta \: when \: \theta \: is \: acute\: angle[/tex]
[tex] \sf \cos^{2}(\theta) - \sin^{2}(\theta) =2-5 \cos(\theta) [/tex]
[tex]\text{note:explanation is a must}[/tex]

Answers

Answer 1

Answer:

θ = [tex]\frac{\pi }{3}[/tex] (60° )

Step-by-step explanation:

Using the identity

sin²x + cos²x = 1 ⇒ sin²x = 1 - cos²x

Given

cos²θ - sin²θ = 2 - 5cosθ

cos²θ - (1 - cos²θ) = 2 - 5cosθ

cos²θ - 1 + cos²θ = 2 - 5cosθ

2cos²θ - 1 = 2 - 5cosθ ( subtract 2 - 5cosθ from both sides )

2cos²θ + 5cosθ - 3 = 0 ← in standard form

(cosθ + 3)(2cosθ - 1) = 0 ← in factored form

Equate each factor to zero and solve for θ

cosθ + 3 = 0

cosθ = - 3 ← not possible as - 1 ≤ cosθ  ≤ 1

2cosθ - 1 = 0

cosθ = [tex]\frac{1}{2}[/tex] , so

θ = [tex]cos^{-1}[/tex] ([tex]\frac{1}{2}[/tex] ) = [tex]\frac{\pi }{3}[/tex] ( or 60° )

Answer 2

Answer:

[tex] \huge \boxed{ \boxed{\blue{ { \theta = 60}^{ \circ} }}}[/tex]

Step-by-step explanation:

to understand thisyou need to know about:trigonometryPEMDASlet's solve:[tex] \sf \: rewrite \: \sin ^{2} ( \theta) \: as \: 1 - \cos ^{2} ( \theta) : \\ \sf \implies \: \cos ^{2} ( \theta) - (1 - \cos ^{2} ( \theta)) = 2 - 5 \cos( \theta) [/tex][tex] \sf \: remove \: parentheses \: and \: change \: its \: sign : \\ \sf \implies \: \cos ^{2} ( \theta) - 1 + \cos ^{2} ( \theta)) = 2 - 5 \cos( \theta) [/tex][tex] \sf \: add : \\ \sf \implies \: 2\cos ^{2} ( \theta) - 1 = 2 - 5 \cos( \theta) [/tex][tex] \sf \: move \: left \: hand \: sides \: expression \: to \: right \: hand \: sides \: : \\ \sf \implies \: 2\cos ^{2} ( \theta) + 5 \cos( \theta) - 1 -2 = 0[/tex][tex] \sf \: rewrite \: 5\cos( \theta) \: as \: 6 \cos( \theta) - \cos( \theta) : \\ \sf \implies \: 2\cos ^{2} ( \theta) + 6 \cos( \theta) - \cos( \theta) - 3 = 0[/tex][tex] \sf \:factor \: out \: 2 \cos( \theta) \: and \: - 1 : \\ \sf \implies \: 2\cos ( \theta)( \cos( \theta) + 3 ) -1( \cos( \theta) + 3) = 0[/tex][tex] \sf \: group: \\ \sf \implies \: (2\cos( \theta) - 1) ( \cos( \theta) + 3 ) = 0[/tex][tex] \sf \: rewrite \: as \: two \: seperate \: equation: \\ \sf \implies \: \begin{cases}2\cos( \theta) - 1 = 0\\ \cos( \theta) + 3 = 0 \end{cases} [/tex][tex]\sf add \: 1 \: to \: the\: first \: equation \: and \: substract \: 3 \: from \: the \: second \: equation: \\ \sf \implies \: \begin{cases}2\cos( \theta) = 1\\ \cos( \theta) = - 3 \end{cases} [/tex]

[tex] \sf the \: second \: eqution \: is \: false \: \\ \sf because \: - 1 \leqslant \cos( \theta) \leqslant 1 \: \\ \sf but \: we \: can \: still \: work \: with \: the \: second \: equation[/tex]

[tex] \sf substract \: both \: sides \: by \: 2 : \\ \implies\frac{ 2\cos( \theta) }{2} = \frac{1}{2} \\ \implies\cos( \theta) = \frac{1}{2} \\ \therefore \: \theta \: = {60}^{ \circ} [/tex]


Related Questions

Complete the table.
f(y) = 4y2 - 4v
f(v
-4
-3
-2
-1

Answers

Answer:

f(y) = 4y2 - 4v

f(y) = 4y² - 4(-4) = 4y² + 16

f(y) = 4y² - 4(-3) = 4y² + 12

f(y) = 4y² - 4(-2) =4y² + 8

f(y) = 4y² - 4(-1) = 4y² + 4

Step-by-step explanation:

An engineer is designing a large steel pad to be installed on the deck of an aircraft carrier. Its total volume will be 18 yd^3. A scale model made of the same material measuring 6 feet by 4.5 feet and 4 inches thick weighs 75 lbs. If the steel costs $55/lb, how much will the material for the full-sized steel pad cost?

a) 12,375.00
b) 55,687.50
c) 82,500.00
d) 222,750.00

Answers

Answer:

The cost of the material for the full-sized pad is;

d) 222,750.00

Step-by-step explanation:

The parameters of the steel pad and the scale model are;

The volume of the deck = 18 yd³

The dimensions of the model of the same material = 6 feet by 4.5 feet and 4.5 inches thick

The weight of the sample, m₂ = 75 lbs

The cost of the steel, P = $55/lb

The dimensions of the sample in yards are;

6 feet = 2 yards, 4.5 feet = 1.5 yards, and 4 inches = 0.[tex]\overline 1[/tex] yards

The volume of the sample, V₂ = 2 yd. × 1.5 yd. × 0.[tex]\overline 1[/tex] yd. =  (1/3) yd.³

The density of the sample material, ρ = m₂/V₂

∴ The density of the sample material, ρ = 75 lbs/((1/3)yd.³) = 225 lbs/yd³

Therefore, the density of the material of the pad, ρ = 225 lbs/yd³

The mass of the steel  pad, m₁ = ρ × V₁

∴ The mass of the steel  pad, m₁ = 225 lbs/yd³ × 18 yd³ = 4,050 lbs

The cost of the material for the full-sized steel pad, C = m₁ × P

∴ C = 4,050 lbs × $55/lb = $222,750


8
z
5
+
4
y

4
z
3
+
z
8
z
5
+
4
y
-
4
z
3
+
z

Answers

Answer:

What???

Step-by-step explanation:

Cant see it?????

enter the value for x that makes the equation, 4(x - 4) = 12x + 16 true.

Answers

Answer:

False your answer will 4x-16

Step-by-step explanation:

you have to distribute 4 to x and 4 to 4. so you will do 4*x=4x and 4*4=16. Now you still have the subtraction sign so your answer will be 4x-16.

5 x / 3 > 5 Fill in the blank with a numerator or denominator to make the number sentence
true.

Answers

Answer:

Any number above 4 will make this true.

Step-by-step explanation:

(5 x 4)/ 3 = 20/3 = 6.67 > 5

Answer:

Any number greater than 3.

Step-by-step explanation:

If you multiply 5 by any number greater than 3 and then divide it by 3 it will result in a number bigger than 5.

If you multiply the 5 by a number less than three, and then divide it by 3 it will result in a number less than 5 which makes the equation false.

You also can't multiply 5 by 3 and then divide it by 3 because it will make the answer equal to 5. This makes the equation false.

Your school raised 125% of its fundraising goal.The School raised $4500.What was the goal?

Answers

Answer:

3600

Step-by-step explanation:

125%=4500

5*25%=4500

25%=900

125%-25%=100%

4500-900=3600

-4n+3>23
A. -5
B. 5
C. -9
D. -20
E. 20

Answers

it will be 20 after u subtract

price of
with a
Find the net Price
an order with a
list
price of $600 and
a trade
discount series of 15/10/5

Answers

Answer:

the questions is not making sense or lacking other information can you edit your question

Pls help Brainelist if correct

The first triangle is dilated to form the second triangle. What is the scale factor? Please show your math work step by step.

Answers

I would help if there was a picture, but there isn’t a picture attached

Which one of these statements correctly states Pythagoras' Theorem for the following diagram?
a) d 2 = e 2 − f 2
b) d 2 = e 2 + f 2
c) e 2 = d 2 + f 2
d) f 2 = d 2 + e 2

Answers

Answer:

I couldn't really read the problem that well, but if there's an e^2+f^2=d^2, then that's probably the correct option.

Step-by-step explanation:

Find slope of line that passes through the points (2,-5) and (3,4).

Answers

Answer:

The slope is 9/1 or just 9.

Step-by-step explanation:

I used the y1-y2/x1-x2 slope formula.

Circle A is defined as (x-5)^2+(y-6)^2=16, and circle B is defined as (x+3)+(y+2)^2=9. Which transformation of circle A shows that circle B is similar?

Answers

Answer: The answer is D

Step-by-step explanation:

Circle A has translated 2 units to the right and  8 units up to produce circle B ad circle B was reduced by a factor of 3/4

Transformation of coordinates

Given the equation of circles A and B defined as  (x-5)^2+(y-6)^2=16 and (x+3)+(y+2)^2=9

The scale factor of a dilation is given as:

k = √9/√16

k = 3/4

From the centers, we can see that circle A has translated 2 units to the right and 8 units up to produce circle B

Learn more on translation here: https://brainly.com/question/1046778

Please help I will mark you brainlest and give you 30 point!!

Answers

Answer:

im not sure but i think its x=6

Multiply o binomial by a trinomial
(x-1) (x²+x+1)

Answers

Answer:

Is this helpful or wrong?

Answer:

hey there, the product is x³ - 1

Give the solution to the system

Answers

Answer:

f(x)=x+2g(x)=-1(x-4)

f(x) represents the red line

g(x) represents the green line

if the variable x = 1

1+2=-1(1-4)

3 = -1(1×(-3))

3 = -1×(-3)

3 = 3

Scale on map is Lin 86 mi if actual distance is 35 mi . Between two cities how far apart on the map are they

Answers

Answer:

0.41 cm

Step-by-step explanation:

The scale on the map is 1 in 86 mi.

This means that, 1 cm on the map represents 86 miles in real life, or on earth.

Then we're told that in real life, a distance is 35 miles, and how far they are on the map.

If 1 cm equals 86 miles, then we can say that x cm equals 35 miles

1 cm ----> 86

x cm ----> 35

x * 86 = 35 * 1

x = 35 / 86

x = 0.41 cm

Therefore, they must be 0.41 cm farther or closer apart on the map scale.

Xavier asks Kofi if he can guess how many pancakes he made in the morning. Xavier gives him three clues to guess.
“If the number of pancakes I have is…”
i) is a multiple of 3, it is a number between 1 and 17
ii) is not a multiple of 8, it is a number between 20 and 27
iii) is not a multiple of 12, it is a number between 30 and 37
How many pancakes did Xavier make?​

Answers

Answer:

33

Step-by-step explanation:

Lara employed a residential cleaning service to tidy up her home. They charged her $150 for 3
hours of work. Her neighbor, Roy hired the same agency and paid them $225 for their services.
How many hours did they take to complete the job at Roy's home?

Answers

Answer:

Step-by-step explanation:

Find the rate that was charged for Lara's time

       rate = dollars / hour

The use this rate to calculate how many hours it took to clean Roy's house, since the rates are the same.  Solve for hours.....

      rate for Lara = dollars / hour        =  $150 / 3 hour   =     $50 / hour

     rate for Roy = dollars / hour         Solve for hours

                                                            multiply both sides by hours

     (rate for Roy) (hour) = (dollars / hour) (hour)

     (rate for Roy) (hour) = (hour) (dollars / hour)       right side hours cancel

     (rate for Roy) (hour) = (dollars)     divide both sides by (rate for Roy)

     (rate for Roy) (hour) / (rate for Roy) = (dollars) / (rate for Roy)

                       now the rate for Roy on the leftside cancel

     (rate for Roy) (hour) / (rate for Roy) = (dollars) / (rate for Roy)

     (hour) = (dollars) / (rate for Roy)           Plug in $225 charged to Roy

                                                                     and the $50 / hour rate

   

       hour = $225 / ($50/hour)             ( 1 over 1 / hour )  = hour  

                = $(225/50) hour            think about  1 / (1/2)  = 2  the same with units

      hour =  4.5 hours

     

The solution shown for the equation is incorrect. What is the correct​ solution? What is the​ error?
−9​(3−​r) = 45
−27−9r = 45
−9r = 72
r = −8

The solution is ____

Answers

-9(3-r)=45
-27+9t=45
9r=45+27
R=72/9
R=8
The answer is 8 not -8

pls helpppp!!
Its a math question i suck at math please help!

Answers

I believe it is the first one

48ft= how many yards​

Answers

Answer:

16 yards

Step-by-step explanation:

x is a 2 digit whole number how many digits does the number 10 x

Answers

Answer:

3

Step-by-step explanation:

Lets take 45 as an example, 10(45) = 450

450 is a 3 digit

answer

3

explanation

let's say X=99

99×10 =990

basically any two digit number multiplied by 10 will result in a 3 digit figure

hope it helps

What is the law of negative exponents in word form.

Answers

Answer:

The negative exponent rule tells us that a number with a negative exponent should be put in the denominator, or the numerator, depending on where the number is.

Step-by-step explanation:

7th grade math help pleasee

Answers

Answer:

Step-by-step explanation:

(a) 7x = 56

divide through by 7

x= 8

(b) 4n = 48

divide through by 4

n = 12

(b) 5c = 80

divide through by 5

n = 16

Answer:

a. 8

b. 12

c.  16

Step-by-step explanation:

7x= 56

You have to get x alone so divide

Divide by 7 to get answer (whatever you do to one side, do to the other)

x= 8

EDIT:

4a. 7x=56

7x/7 = 56/7

x= 8

4b. 4x=48

4x/4=48/4

x= 12

4c. 5c= 80

5c/5=80/5

c=16

the same goes for the rest

p.s. pls practice your multiplication as you will need it throughout high school :)

please help__________​

Answers

Answer:

Area = 52√3

A

Step-by-step explanation:

Remark

This is a trapezoid. The formula for a trapezoid is Area = 1/2 (b1 + b2)* h/2

Givens

b1 = 11

b2 = 15

h = 4*√3

Solution

Area = 1/2 (15 + 11 )*4*√3

Area = 1/2(26)*4√4

Area = 13 * 4√3

Area = 52√3

Maria purchased 1/2 pound of cheese for $3.50 at a farmer's market. What would be the cost for 4 pound of cheese?

Answers

Answer:

$28

Step-by-step explanation:

use a proportion:

$/lb = $/lb

3.5/1/2 = x/4

cross-multiply:

1/2x = 14

x = 28

Find the slope of the line. Write your answer in simplest form.

Answers

Answer:

Slope = -3/5

Step-by-step explanation:

slope (m) = y2 - y1 / x2 - x1

m = -2 - 1 / 1 - -4

m = -3 / 1 + 4

m = -3 / 5

You can check the work by counting rise (-3 which means 3 units down) over run (5 which means 5 units to the right)

Answer:

-3/5

Step-by-step explanation:

The line is y=-3/5x-1.4

radical form. ooooooooooo

Answers

Answer:

by using Pythagoras law

h²=p²+b²

7²=4²+b²

b²=49-16

b=√33=5.744

third side is 5.744

Answer:

missing length = 5.74

Step-by-step explanation:

[tex]a^{2} = c^{2} - b^{2}[/tex]

[tex]a^{2} = 7^{2} - 4^{2}[/tex]

[tex]a^{2} = 49 - 16[/tex]

[tex]a^{2} = 33[/tex]

[tex]\sqrt{a^{2} } = \sqrt{33}[/tex]

[tex]a = 5.74[/tex]

John is planning a vegetable garden in the shape of a square. The area of the garden is 100 square feet. What will be the length of each side? Which explanation would be correct? A) 50 feet because you divide 100 by 2 B) 10 feet because you take the square root of 100 C) 25 feet because you have 4 sides of a square D) None of the above

Answers

Answer:c

Step-by-step explanation:

Bc if it’s a square there will be 4 corners and each will have the same number count so u have to put even numbers in each corner and that’s 25 25+25=50 25+25=50 50+50=100

which quotient is greatest ?
A. 24.6 / 0.6
B. 2.46 / 0.06
C. 24.6 / 0.006
D. 2.46 / 0.006

Answers

Answer:

Step-by-step explanation:

Remark

The larger the numerator and the smaller the denominator, the bigger the quotient. Try and get the answer using that rule.

C

24.6 / 0.006 = 4100 Nothing is bigger than that.

Try D

2.46/0.006 =410

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