20: This general power needs to be transformed into its canonical form first:

Conditions
    • arccos(x) > 0,
    • −1 ≤ x ≤ 1,
    • x ≠ 0
give the domain

D( f ) = [−1,0) ∪ (0,1).

Now it is time to find limits at −1 from the right, at 0 from the left and from the right, and at 1 from the left.

Hint on limit at −1 from the right
Hint on limit at 0 from the left
Hint on limit at 0 from the right
Hint on limit at 1 from the left
Answer