21: Conditions x2 − 2x − 3 > 0, x2 + x − 6 > 0 give the domain
D( f ) = (−∞,−3) ∪ (3,∞).
Now it is time to find limits at −∞, at −3 from the left, at 1 from the right, and at ∞.
Hint on limit at −∞ Hint on limit at −3 from the left Hint on limit at 3 from the right Hint on limit at ∞ Answer