Math Problem Statement

Find the value of sin(-11π/3)

Solution

The problem asks for the value of sin(11π3)\sin\left( -\frac{11\pi}{3} \right).

Step-by-Step Solution:

  1. Simplifying the Angle: The angle 11π3-\frac{11\pi}{3} is outside the standard range of 00 to 2π2\pi, so we need to simplify it using the periodicity of the sine function. The sine function has a period of 2π2\pi, meaning sin(θ)=sin(θ+2nπ)\sin(\theta) = \sin(\theta + 2n\pi), where nn is an integer.

    First, let's reduce 11π3-\frac{11\pi}{3} by adding multiples of 2π2\pi: 11π3+2π=11π3+6π3=5π3-\frac{11\pi}{3} + 2\pi = -\frac{11\pi}{3} + \frac{6\pi}{3} = -\frac{5\pi}{3} So, sin(11π3)=sin(5π3)\sin\left( -\frac{11\pi}{3} \right) = \sin\left( -\frac{5\pi}{3} \right).

  2. Finding the Reference Angle: The angle 5π3-\frac{5\pi}{3} lies in the fourth quadrant. To find the reference angle, subtract this from 2π2\pi: 2π5π3=6π35π3=π32\pi - \frac{5\pi}{3} = \frac{6\pi}{3} - \frac{5\pi}{3} = \frac{\pi}{3} So the reference angle is π3\frac{\pi}{3}.

  3. Determining the Sine Value: In the fourth quadrant, sine is negative. The value of sin(π3)\sin\left( \frac{\pi}{3} \right) is 32\frac{\sqrt{3}}{2}, so: sin(5π3)=sin(π3)=32\sin\left( -\frac{5\pi}{3} \right) = -\sin\left( \frac{\pi}{3} \right) = -\frac{\sqrt{3}}{2}

Thus, the value of sin(11π3)\sin\left( -\frac{11\pi}{3} \right) is 32-\frac{\sqrt{3}}{2}.

Would you like more details or have any questions?

Related Questions:

  1. What is the value of cos(11π3)\cos\left( -\frac{11\pi}{3} \right)?
  2. How would you find tan(11π3)\tan\left( -\frac{11\pi}{3} \right)?
  3. What is the period of the sine function, and how is it used in simplification?
  4. Can you explain the concept of reference angles in trigonometry?
  5. How do you determine the sign of a trigonometric function in each quadrant?

Tip:

When simplifying angles in radians, always try to reduce them to their reference angles using the periodic properties of the trigonometric functions.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sine Function
Angle Reduction

Formulas

sin(θ) = sin(θ + 2nπ)

Theorems

Sine periodicity
Reference angle in trigonometry

Suitable Grade Level

Grades 10-12