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Find the value of $ arccos(-1/2) $ and verify it using the unit circle.

Answer 1

Abigail Nelson

Henry Green

To find the value of $\arccos(-1/2)$, we need to determine the angle in the unit circle whose cosine is $-1/2$.

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From the unit circle, we know that:

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$ \cos(\pi – \frac{\pi}{3}) = \cos(\frac{2\pi}{3}) = -1/2 $

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Hence, the value of $\arccos(-1/2)$ is $\frac{2\pi}{3}$.

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Verification:

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Consider the angle $\frac{2\pi}{3}$ in the unit circle, its cosine value is:

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$ \cos(\frac{2\pi}{3}) = -1/2 $

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This matches our original value, verifying that $\arccos(-1/2) = \frac{2\pi}{3}$.

Answer 2

Alex Thompson

John Anderson

To find $arccos(-1/2)$, we need the angle whose cosine is $-1/2$.

We know that:

$ cos(frac{2pi}{3}) = -1/2 $

Thus, $arccos(-1/2) = frac{2pi}{3}$.

Verification: The cosine of $frac{2pi}{3}$ is:

$ cos(frac{2pi}{3}) = -1/2 $

This confirms that $arccos(-1/2) = frac{2pi}{3}$.

Answer 3

Amelia Mitchell

Olivia Lee

To find $arccos(-1/2)$, we determine the angle whose cosine is $-1/2$.

As:

$ cos(frac{2pi}{3}) = -1/2 $

Then, $arccos(-1/2) = frac{2pi}{3}$

Verification: Since:

$ cos(frac{2pi}{3}) = -1/2 $

This verifies that $arccos(-1/2) = frac{2pi}{3}$.