Calculus:Limits

$\lim _{x\to a}f(x)=L,$ When you see this equation it means you are try to let x approaches a.

You may have a question why can't we just write it as

$f(a)=L,$

some times we can't tell what is the F(a) equals to.

example 1

$\lim _{x\to a}f(x)={x^{2}-1 \over x-1}$

But If a = 1 then you will get ${1^{2}-1 \over 1-1}={0 \over 0}$