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Answer 1

Abigail Nelson

Henry Green

To find all solutions for $ \cos(\theta) = -\frac{1}{2} $ in the range $ [0, 2\pi] $, we need to determine where the cosine function is -1/2 on the unit circle:

Cosine is negative in the second and third quadrants. The reference angle for $ \cos^{-1}(-\frac{1}{2}) $ is $ \frac{\pi}{3} $.

Therefore, the solutions are:

$ \theta_1 = \pi – \frac{\pi}{3} = \frac{2\pi}{3} $

$ \theta_2 = \pi + \frac{\pi}{3} = \frac{4\pi}{3} $

Thus, the solutions are $ \theta = \frac{2\pi}{3} $ and $ \theta = \frac{4\pi}{3} $.

Answer 2

Alex Thompson

Emily Hall

To solve $ cos( heta) = -frac{1}{2} $ in the range $ [0, 2pi] $, identify where cosine is negative and has a value of -1/2:

– It occurs in the second quadrant at $ heta = pi – frac{pi}{3} = frac{2pi}{3} $.

– It also occurs in the third quadrant at $ heta = pi + frac{pi}{3} = frac{4pi}{3} $.

The solutions are $ heta = frac{2pi}{3} $ and $ heta = frac{4pi}{3} $.

Answer 3

Amelia Mitchell

Maria Rodriguez

Solve $ cos( heta) = -frac{1}{2} $ in $ [0, 2pi] $:

The solutions are $ heta = frac{2pi}{3} $ and $ heta = frac{4pi}{3} $.