Math Problem Statement

Find all solutions of the given equation: 2cos(θ) + √3 = 0.

Solution

To solve the equation 2cos(θ)+3=02 \cos(\theta) + \sqrt{3} = 0, follow these steps:

  1. Rearrange the equation: 2cos(θ)=32 \cos(\theta) = -\sqrt{3}

  2. Divide both sides by 2: cos(θ)=32\cos(\theta) = -\frac{\sqrt{3}}{2}

  3. Find the reference angle: The reference angle for cos(θ)=32\cos(\theta) = \frac{\sqrt{3}}{2} is θ=π6\theta = \frac{\pi}{6}.

  4. Determine the quadrants: Since cos(θ)=32\cos(\theta) = -\frac{\sqrt{3}}{2}, θ\theta is in the second and third quadrants.

  5. Calculate the angles:

    • Second quadrant: θ=ππ6=5π6\theta = \pi - \frac{\pi}{6} = \frac{5\pi}{6}
    • Third quadrant: θ=π+π6=7π6\theta = \pi + \frac{\pi}{6} = \frac{7\pi}{6}
  6. General solution: The general solutions are: θ=5π6+2kπ,7π6+2kπ\theta = \frac{5\pi}{6} + 2k\pi, \frac{7\pi}{6} + 2k\pi where kk is any integer.

The solutions are 5π6+2kπ,7π6+2kπ\frac{5\pi}{6} + 2k\pi, \frac{7\pi}{6} + 2k\pi.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Cosine Function
General Solutions of Trigonometric Equations

Formulas

cos(θ) = -√3 / 2
General solution for cosine: θ = α + 2kπ or θ = -α + 2kπ, where k is an integer

Theorems

Reference Angle Theorem
Cosine Function Symmetry in Trigonometric Quadrants

Suitable Grade Level

Grades 10-12