# one sided limit

• Jan 1st 2008, 04:52 AM
wutever
one sided limit
heeey

lim x^4-1 / x - 1
x-> 1+

how to do it, how to find one sided limit ???
the answer is 4
• Jan 1st 2008, 05:29 AM
topsquark
Quote:

Originally Posted by wutever
heeey

lim x^4-1 / x - 1
x-> 1+

how to do it, how to find one sided limit ???
the answer is 4

$\lim_{x \to 1^+} \frac{x^4 - 1}{x - 1} = \lim_{x \to 1^+} \frac{(x^2 + 1)(x^2 - 1)}{x - 1}$

$= \lim_{x \to 1^+} \frac{(x^2 + 1)(x + 1)(x - 1)}{x - 1}$

$= \lim_{x \to 1^+}(x^2 + 1)(x + 1) = 2 \cdot 2 = 4$

-Dan