Sections in the Chapter
20.1 Informal approach to limit
20.2 Formal approach to limit
20.3 Evaluation of left hand and right hand limits
20.4 Difference between the value of a function at a point and the limit at a point
20.5 The algebra of limits
20.6 Evaluation of limits
We can approach a given number ‘a’ on the real line from its left hand side by increasing numbers which are less than ‘a’. It means starting from a- δ and increasing to reach a.
We can also approach a given number ‘a’ on the real line from its right hand side by decreasing numbers which are greater than ‘a’. It means starting from a+δ and decreasing to reach a.
Hence there are two types of limits – left hand limit and right hand limit.
For some functions both these limits are equal at a point and for some functions they are not equal.
If both are equal we say lim (x→a) f(x) exists. Otherwise it does not exist.
Updated 17 Jan 2016, 2 Dec 2008