19: The condition x − 1 > 0 gives the domain

D( f ) = (−∞,1) ∪ (1,∞).

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

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