Math Problem Statement

derive value of sin(pie/11)

Solution

To derive the value of sin(π11)\sin\left(\frac{\pi}{11}\right), we can't express it exactly in terms of elementary functions like we can for certain angles (e.g., π6,π4,\frac{\pi}{6}, \frac{\pi}{4}, etc.). However, we can use an approximation method or express the value as part of a known polynomial identity.

Approximate Value of sin(π11)\sin\left(\frac{\pi}{11}\right):

Using a calculator or known sine tables, the approximate value of sin(π11)\sin\left(\frac{\pi}{11}\right) is:

sin(π11)0.28176\sin\left(\frac{\pi}{11}\right) \approx 0.28176

Exact Form in Terms of Roots of Unity:

Another approach is related to solving for the roots of the equation sin(11θ)=0\sin(11\theta) = 0, but deriving the exact algebraic form is highly complex and involves solving a degree-10 polynomial (related to Chebyshev polynomials and cyclotomic fields).

If you'd like more details on either method, I can guide you further!

Would you like a more detailed derivation or explanation on any of the steps?


Here are five relative questions for deeper understanding:

  1. How is the sine function defined for various angles?
  2. How can we use the unit circle to interpret trigonometric values?
  3. What are some key differences between exact and approximate values in trigonometry?
  4. Can you express other trigonometric values for special angles like π7\frac{\pi}{7} or π13\frac{\pi}{13}?
  5. What are the properties of Chebyshev polynomials?

Tip: To improve accuracy, especially for small angles, you can use the series expansion for sine. For small values of xx, sin(x)xx36+x5120\sin(x) \approx x - \frac{x^3}{6} + \frac{x^5}{120} - \dots.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sine Function
Approximation Methods
Roots of Unity

Formulas

sin(x) ≈ x - (x^3)/6 + (x^5)/120 - ... for small angles
sin(11θ) = 0

Theorems

Chebyshev Polynomials
Cyclotomic Fields

Suitable Grade Level

Grades 11-12