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Solve −2+6cosx=8−4cosx for 0∘≤x≤180∘.
A. x=30∘
B. x=45∘
C. x=60∘
D. x=90∘

1 Answer

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Final answer:

After combining like terms and solving the equation, the cosine value equals 1, which corresponds to an angle of 0° within the given interval. However, this angle is not listed in the provided answer choices, which suggests an error in the question or answer options.

Step-by-step explanation:

To solve the equation −2+6cosx=8−4cosx for 0°≤x≤180°, we first combine like terms:

  • Add 4cosx to both sides: −2 + 6cosx + 4cosx = 8
  • Combine the cosx terms: 10cosx = 10
  • Divide both sides by 10: cosx = 1

Now, we need to find the value of x for which the cosine is equal to 1. Within the given interval, x can only be 0° as cos(0°) = 1. However, since 0° is not an option given in the question, this indicates there has been a typo or a misunderstanding in the question or provided answers since cos(180°) = -1. Therefore, none of the provided options are correct.

It's important to know the basic trigonometric values and to always verify that the calculated result falls within the given interval.

User Vj Sreenivasan
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