1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
AlekseyPX
3 years ago
12

Solve 2cos x+2cos 2x=0 on the interval [0,2pi)

Mathematics
2 answers:
Anarel [89]3 years ago
8 0

Answer:

The answers are B and C, 3π/4 and 5π/4

Step-by-step explanation:

rjkz [21]3 years ago
6 0
2cosx+2cos2x=0 \\ -2sin^2x+2cos^2x+2cosx=0 \\ -2(1-cos^2x)+2cos^2x+2cosx=0 \\ -2+2cos^2x+2cos^2x+2cosx=0 \\ 4cos^2x+2cosx-2=0 \\ t=cos x \\ 4t^2+2t-2=0 \\ \Delta=4+32=36 \\ t_1= \frac{-2-6}{8}=-1 \\ t_2= \frac{-2+6}{8}= \frac{1}{2}  \\ cos x=-1 \lor cos x= \frac{1}{2}    \\ x=-\pi \lor x= \frac{5\pi}{3}
You might be interested in
Angelica says the tangent is the ratio of the length of the leg opposite angle A ∠ A over the length of the leg adjacent to angl
Tpy6a [65]

Based on the trigonometry ratios and the Pythagorean theorem both of them were incorrect.

Cos A = 4/5; Sin A = 3/5

<h3>What is the Trigonometry Ratios?</h3>

The Trigonometry ratios relates the length of the sides of a right triangles. They are given as:

  • Sine ratio, sin ∅ = opp/hyp
  • Cosine ratio, cos ∅ = adj/hyp
  • Tangent ratio, tan ∅ = opp/adj.

<h3>What is the Pythagroean Theorem?</h3>

If two sides of a right triangle are known the third side can be determined using the Pythagorean theorem, which is given as, c² = a² + b², where and b are legs, and c is the hypotenuse of the right triangle.

1. Given that tan A = 3/4, it is not necessarily true that BC MUST have a length of 3 units, and AC MUST have a length of 4 units, because:

If BC = 9 units and AC = 12 units, the it will give us the same tangent ratio as:

tan A = 9/12 = 3/4.

Therefore, Angelica's mistake is stating that BC MUST be 3 units, and AC MUST be 4 units.

2. Knowing two length of the sides of a right triangle is enough information needed to find the length of the third side using the Pythagorean theorem, so Graceilla is incorrect.

3. Find AC using the Pythagorean theorem:

AB = √(3² + 4²)

AB = 5 units.

Cos A = adj/hyp = AC/AB

Cos A = 4/5

Sin A = opp/hyp = BC/AB

Sin A = 3/5

Learn more about the trigonometry ratios on:

brainly.com/question/10417664

3 0
2 years ago
What is 10 1/7 divided by 5 as a fraction or mixed number?
juin [17]
= 2 1/35
75/7 divided by 5/1
71x1/ 7x5
= 71/ 35
Therefore, 2 1/35
7 0
3 years ago
List all factor for each number 100. 65. 70
LiRa [457]
The factors of 100 are 1, 2, 4, 5, 10, 20, 25, 50, and 100 .

The factors of 65 are 1, 5, 13, and 65 .

The factors of 70 are 1, 2, 5, 7, 10, 14, 35, and 70 .
3 0
4 years ago
Read 2 more answers
Which expression is equivalent to 5x + 3y - 2x?<br><br> 3x<br> 6x<br> 3x + 3y<br> 7x + 3y
Tcecarenko [31]
The answer to the question is:

3x + 3y
4 0
3 years ago
Read 2 more answers
MATH HELP please i will mark BRAINLIEST
frutty [35]
I hope this helps! Just follow the instructions.

3 0
3 years ago
Other questions:
  • 4.   What is step 2 in the problem-solving process?
    6·2 answers
  • 1.A spherical tank has a radius of 6 yards. It is filled with a liquid that costs $7.15 per cubic yard.
    9·2 answers
  • Find the value of x in the triangle. <br>A. 7°<br>B. 293°<br>C. 113°<br>D. 67°
    9·2 answers
  • Ben claims that 12 is a factor of 24.how can you check whether he is correct?
    11·1 answer
  • Which of these is a geometric sequence?
    7·1 answer
  • What is the slope of the line graphed on the coordinate plane?
    5·2 answers
  • What is the solution of the following linear system of equations? 4y=−5x−2, x−4y=14
    15·1 answer
  • PLEASE HELP I mixed everything up and now I dont know!!
    6·2 answers
  • Can i have some help please( BRAINLLEST)
    13·1 answer
  • Do 9a, 9b, 9c please quick due in 5 minutes also pleaseeee show step by step thanks I will mark brainlest and give extra points
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!