Determining all values of Θ (gr. 11 math)

  • MHB
  • Thread starter eleventhxhour
  • Start date
  • Tags
    Gr
In summary, the conversation discusses trigonometric ratios and how to use them to determine values of Θ within a certain range. For part c), the solution is Θ = 151° or 209°, found using the identity \cos\left(360^{\circ}-\theta\right)=\cos(\theta). For part d), the solutions are Θ = 7° or 187°, as the equation \tan(-\theta)=\tan(\theta) does not hold true.
  • #1
eleventhxhour
74
0
8) Use each trigonometric ratio to determine all values of Θ, to the nearest degree if 0°≤ Θ ≤ 360°.

c) cosΘ = -0.8722

So, this is what I did for this question:
Θ=cos^-1(-0.8722)
Θ = 151°

This is correct, according to the textbook. However, it also gives another answer: 209°. How do you get this using the equations? (like sin (360° - Θ) = -sinΘ, tan (180° + Θ) = tanΘ, etc.)

d) cotΘ = 8.1516.

So, here's what I did for this part:
Θ = 7°
tan(180+7)= 187°
tan(360-7) = 353°

HOWEVER, the textbook only has the answers 7° and 187°. Why wouldn't 353° be correct?

Thanks!
 
Mathematics news on Phys.org
  • #2
For part c) consider the identity:

\(\displaystyle \cos\left(360^{\circ}-\theta\right)=\cos(\theta)\)

For part d), you are essentially trying to assert that:

\(\displaystyle \tan(-\theta)=\tan(\theta)\)

Is this true?
 

FAQ: Determining all values of Θ (gr. 11 math)

1. How do you determine all values of Θ?

To determine all values of Θ, you must first identify the trigonometric function involved in the equation. Then, use the inverse trigonometric function to isolate Θ and solve for its values. This can be done by using a unit circle or trigonometric identities.

2. What is the importance of determining all values of Θ?

Determining all values of Θ allows us to find all possible solutions to an equation involving trigonometric functions. This is important in many real-world applications, such as navigation, physics, and engineering.

3. What are the common trigonometric functions used in determining all values of Θ?

The most common trigonometric functions used are sine, cosine, and tangent. However, other functions such as secant, cosecant, and cotangent may also be involved in the equation.

4. Can there be more than one solution when determining all values of Θ?

Yes, there can be multiple solutions when determining all values of Θ. This is because trigonometric functions are periodic, meaning they repeat their values after a certain interval. Therefore, there may be more than one value of Θ that satisfies the equation.

5. How can technology assist in determining all values of Θ?

Technology, such as graphing calculators and online calculators, can be helpful in determining all values of Θ. These tools can quickly and accurately calculate the solutions to trigonometric equations, making the process more efficient and less prone to human error.

Back
Top