In Exercises 1–4, fill in the blank. If not possible, state the reason. (Note: The notation x → ­c⁺ indicates that x approaches c from the right and x → ­c^ indicates that x approaches c from the left.)

1. As x → 1 ^-, the value of arcsin x → .

2. As x → 1 ^-, the value of arccos x → .

3. As x → ∞, the value of arctan x → .

4. As x → -1 ⁺, the value of arcsin x → .