AP Precalculus -3.9 Inverse Trigonometric Functions- MCQ Exam Style Questions - Effective Fall 2023
AP Precalculus -3.9 Inverse Trigonometric Functions- MCQ Exam Style Questions – Effective Fall 2023
AP Precalculus -3.9 Inverse Trigonometric Functions- MCQ Exam Style Questions – AP Precalculus- per latest AP Precalculus Syllabus.
Question
(B) Domain: \([-1, 1]\), Range: \([-\frac{\pi}{2}, \frac{\pi}{2}]\)
(C) Domain: \([-\frac{\pi}{2}, \frac{\pi}{2}]\), Range: \([-\frac{1}{2}, \frac{1}{2}]\)
(D) Domain: \([-\frac{\pi}{2}, \frac{\pi}{2}]\), Range: \([-1, 1]\)
▶️ Answer/Explanation
For the original function \( f(x) = \frac{1}{2}\sin x \) on \( -\frac{\pi}{2} \leq x \leq \frac{\pi}{2} \):
– Domain of \( f \): \( [-\frac{\pi}{2}, \frac{\pi}{2}] \)
– Range of \( f \): Since \(\sin x\) ranges from \(-1\) to \(1\) over this interval, \( \frac{1}{2}\sin x \) ranges from \(-\frac{1}{2}\) to \(\frac{1}{2}\).
For the inverse function \( f^{-1} \), the domain and range swap:
– Domain of \( f^{-1} \) = Range of \( f \) = \([-\frac{1}{2}, \frac{1}{2}]\)
– Range of \( f^{-1} \) = Domain of \( f \) = \([-\frac{\pi}{2}, \frac{\pi}{2}]\)
✅ Answer: (A)
Question
▶️ Answer/Explanation
For a sinusoidal function to be invertible, it must be one-to-one on an interval. The longest such interval on a sine or cosine wave is half a period where the function is strictly increasing or decreasing.
From the graph (described in the PDF), the period is 4, so half-period is 2. This gives the longest interval for an inverse.
✅ Answer: (B)
