Answer:
As x → ∞, f (x) → −∞
As x → −∞, f (x) → ∞.
Explanation:
Method 1:
To solve this, we can simply substitute a large number as ∞ into the equation.
For example, as x->999 (∞), f(x)->-998999000 (-∞).
as x->-999 (-∞), f(x)->995006998 (∞)
Therefore achieving your answer of
As x → ∞, f (x) → −∞
As x → −∞, f (x) → ∞.
Method 2:
We can alternatively solve this by substituting ∞ as x.
As x->∞, f(∞) = 1-2(∞)^2-(∞)^3
= 1-∞-∞
= -∞
As x->-∞, f(-∞) = 1-2(-∞)^2-(-∞)^3
= 1 +2(∞)+(∞)
= ∞
Thus, we can say
As x → ∞, f (x) → −∞
As x → −∞, f (x) → ∞.