Find the Exact Solution to the Equation Without a Calculator $\cos ^ { - 1 } ( \cos x ) = 1.8$

question 68

Multiple Choice

Find the exact solution to the equation without a calculator.
- $\cos ^ { - 1 } ( \cos x ) = 1.8$

• A) \(0.9\)
• B) \(3.6\)
• C) \(1.8\)
• D) 0