Limits at Infinity:

Consider a function f defined for large positive ( or negative ) values of x, as x increases indefinitely in the positive ( or negative ) direction. If the value of f(x) approaches a number b as x increases (or decreases ) indefinitely , then the limit of f(x) as x increases (or decreases ) indefinitely is equal to b, denoted as :

lim_x®+¥ f(x) = b or lim_x®-¥ f(x) = b