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Solve the equation 2cos(x)+1=0, 0< or equal to x< or equal to 2pi. Show all of your work.

1 Answer

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Answer:

x = 5π/3

Stop-by-step explanation:

We are given the equation:

2cos(x) + 1 = 0

Subtracting 1 from both sides, we get:

2cos(x) = -1

Dividing by 2, we get:

cos(x) = -1/2

We know that the cosine function is negative in the second and third quadrants of the unit circle. In the second quadrant, the reference angle for which the cosine is 1/2 is π/3, and in the third quadrant, the reference angle is also π/3. Therefore, the solutions for x are:

x = π + π/3 = 4π/3 or x = 2π - π/3 = 5π/3

Since the given range is 0 ≤ x ≤ 2π, the only solution in that range is:

x = 5π/3

Therefore, the solution of the equation 2cos(x) + 1 = 0 in the given range is x = 5π/3.
User Roman Karagodin
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