Math Problem Statement

sin−1(sin(7𝜋/6))

Solution

To evaluate sin1(sin(7π/6))\sin^{-1}(\sin(7\pi/6)), let’s carefully consider the behavior of the inverse sine function sin1\sin^{-1} (also known as arcsin):

Steps:

  1. Simplify sin(7π/6)\sin(7\pi/6):

    • sin(7π/6)\sin(7\pi/6) corresponds to an angle in the third quadrant where sine is negative.
    • The reference angle for 7π/67\pi/6 is π/6\pi/6, and since it is in the third quadrant, sin(7π/6)=sin(π/6)=12\sin(7\pi/6) = -\sin(\pi/6) = -\frac{1}{2}.

    Therefore, sin(7π/6)=12\sin(7\pi/6) = -\frac{1}{2}.

  2. Find sin1(12)\sin^{-1}(-\frac{1}{2}):

    • The function sin1\sin^{-1} (arcsin) returns values in the range [π/2,π/2][-\pi/2, \pi/2].
    • For sin1(12)\sin^{-1}(-\frac{1}{2}), the angle within this range that satisfies sin(θ)=12\sin(\theta) = -\frac{1}{2} is θ=π/6\theta = -\pi/6.

Final Answer:

sin1(sin(7π/6))=π6.\sin^{-1}(\sin(7\pi/6)) = -\frac{\pi}{6}.

Would you like a detailed explanation of inverse trigonometric properties or additional examples?


Follow-up Questions:

  1. What are the domain and range of sin1(x)\sin^{-1}(x)?
  2. How can you verify sin1(sin(x))\sin^{-1}(\sin(x)) for any angle xx?
  3. What happens if the input angle is not in the principal range of arcsine?
  4. Can you generalize the result for sin1(sin(nπ+x))\sin^{-1}(\sin(n\pi + x))?
  5. How does cos1(cos(x))\cos^{-1}(\cos(x)) differ in behavior from sin1(sin(x))\sin^{-1}(\sin(x))?

Tip: Always remember that the range of sin1(x)\sin^{-1}(x) is restricted to [π/2,π/2][-\pi/2, \pi/2], which is crucial for interpreting results.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Inverse Trigonometric Functions
Principal Value

Formulas

sin(x)
sin⁻¹(x)

Theorems

Range of sin⁻¹(x)
Behavior of sin⁻¹(sin(x)) within principal range

Suitable Grade Level

Grades 11-12