How to algebraically manipulate a limit of the form 00
Factoring can help us evaluate a limit. For example, we already
looked at the limit limx→1x2−1x−1
Since
x2−1=(x−1)(x+1), we have limx→1x2−1x−1=limx→1(x−1)(x+1)x−1=limx→1(x+1)=2.
Canceling the factors of x−1 from the numerator and denominator
is OK for all values of xexcept x=1.
However, we're only looking at what happens when x is close to 1, not
equal to 1, so the cancellation makes sense.