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

WILL GIVE BRAINLEST

Keisha conducts a survey to determine how many siblings each of her classmates has. The data are shown below.

0, 1, 0, 2, 2, 1, 3, 0, 4, 0, 1, 2

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A. 0.75
B. 1
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D. 2

Answers

Answer:

c

Step-by-step explanation:a

add up 0, 1, 0, 2, 2, 1, 3, 0, 4, 0, 1, 2

Answer:

C. 1.3

Step-by-step explanation:

0, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 4

To find the mean, or average, we add up all the numbers to get the total number of siblings (16), and divide by the number of classmates she surveyed (12). 16/12 = 1.3

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A plot of land for sale has a width of x ft, and a length that is 8 ft. less than its width. A farmer will only purchase the land if it measures 240 ft.
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Answers

Answer:

a

Step-by-step explanation:

Answer:

dunno

Step-by-step explanation:

25- 3x = 40 what is x

Answers

Simplifying
25 + -3x = 40

Solving
25 + -3x = 40

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-25' to each side of the equation.
25 + -25 + -3x = 40 + -25

Combine like terms: 25 + -25 = 0
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-3x = 40 + -25

Combine like terms: 40 + -25 = 15
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Divide each side by '-3'.
x = -5

Simplifying
x = -5

Which equation represents a linear function

Answers

Answer: B

Step-by-step explanation:

jane and kate share $240 in the ratio 5:7. show that kate receives $140

Answers

Answer:

$140

Step-by-step explanation:

5 + 7 = 12

240/12 = 20

20 x 7 = $140

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Answers

Answer:

m∠3 = 127°

Step-by-step explanation:

From the given picture,

Two parallel lines have been given.

Angle 3 and another angle measuring 53° are located on a point of a straight line.

Therefore, both the angles will be supplementary.

m(∠3) + 53° = 180° [Property of supplementary angles]

m(∠3) = 180° - 53°

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bill bowled 3 games at a bowling alley and rented shoes, spending a total of $9.00. leann bowled 5 games at a the bowling alley and rented shoes, spending a total of $14.00. how much does it cost to bowl a game

Answers

The cost to bowl a game is $2.5.

What is Equation?

Two or more expressions with an Equal sign is called as Equation.

Let g  represent the cost of bowling a game and s represent the cost of renting shoes.

Bill bowled 3 games at a bowling alley and rented shoes, spending a total of $9.00

3g+s=9..(1)

Leann bowled 5 games at a the bowling alley and rented shoes, spending a total of $14.00.

5g+s=14..(2)

Subtract equation 2 from 1

3g+s-5g-s=9-14

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Divide both sides by 2

g=2.5

Hence, the cost to bowl a game is $2.5.

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https://brainly.com/question/10413253

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Packs of dark chocolate contain 5 cookies, and packs of white chocolate cookies contain 6 cookies. If Daniel bought the same number of cookies of each the, what is the smallest number of each type he could have bought?

Answers

Answer:

30

Step-by-step explanation:

30 because 5 x 6=30 and 6 x 5= 30

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Answers

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Step-by-step explanation:

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Answers

Answer:

5(2x + 4) = 10(x + 2)

Step-by-step explanation:

answer is 0 so it has infinite solutions

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Answers

Answer:

50%

Step-by-step explanation:

Half of the numbers in the sequence are odd, so there's a 50% to have gotten an odd number randomly. Therefore, P = 50%

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Use the​ (x,y) coordinates in the figure to find the value of tan (2(pi)/3) or state that the expression is undefined.
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Answers

Answer:

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Answers

Answer:

24.1

Step-by-step explanation:

7.4x3=22.2

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Answers

V = pi*r^2*h
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Answers

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Step-by-step explanation:

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Answers

Answer:

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Step-by-step explanation:

As you can from the graph, the graph ONLY touches y = 0 at ONLY x = -4.

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A cube has a volume of 64. What is the side length of one side
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Answers

Answer:

4

Step-by-step explanation:

volume is equal to a x a x a

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Answers

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Step-by-step explanation:

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Answers

Question:

1 + 1 = ? help now please asap!

Answer:

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Answers

Answer:

122

Step-by-step explanation:

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Answers

Answer:

m<Y = 68°

Step-by-step explanation:

A tangent drawn to a circle makes a 90° angle with the radius that intersects it at the point of tangency. That means that m<X = 90°.

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Answers

40=.60x
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Answers

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Answer:

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Step-by-step explanation:

Answer

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Answers

Answer:

I believe that would be 12 because

Step-by-step explanation:

if 2x - 7y = 10

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Out of 1,200 students that attend Norman Rockwell Middle School, how many would most likely sign up for after school tutoring, if 48 out of 80 students randomly surveyed said they would like to have extra help after school?

Answers

Answer:

720

Step-by-step explanation:

Out of 80 students the no. of students who sign up=48

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Answers

Answer:

The difference is 8.75

Step-by-step explanation:

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Answers

Answer:

15

Step-by-step explanation:

You know that it takes 3 mins for 45 sit-ups so then you wanna find how much for 1 minute. It shows 3 mins which is 3 times as much as 1 minute. There, 3/3 = 1. then you have to do it with the sit-ups too. so 45/3 = 15

How you use the Pythagorean theorem in 3D.

Answers

Answer:

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Step-by-step explanation:

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2 mm
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Answers

Answer:

A = 14 mm²

Step-by-step explanation:

The area (A) of a triangle is calculated as

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