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Solve cos x + rad 2 = -cos x for over the interval [0, 2pi ]

User Tyler Rash
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2 Answers

4 votes

Answer:

Option C is the answer

Explanation:

Solve cos x + rad 2 = -cos x for over the interval [0, 2pi ]-example-1
User Kostyantyn Ivanov
by
7.9k points
2 votes

cos x + √(2) = -cosx \\ \\ 2 cos x + √(2) = 0 \\ \\ cos x = -(√(2))/(2)

The cosine function is negative in 2nd and 3rd quadrants, So you know that you will have 2 solutions. One between pi/2 and pi, the other between pi and 3pi/2.

Refer to a unit circle to find that

cos ((3\pi)/(4)) = -(√(2))/(2) \\ \\ cos ((5\pi)/(4)) = -(√(2))/(2)

Final Answer:

x = (3\pi)/(4), (5\pi)/(4)
User Bharat
by
8.3k points

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