Introduction to Series

Introduction to Series: The notion of series is closely related to the sum of numbers. In fact, whenever one hears the word series, the first thing to come to mind is the sum of numbers. This is the basic difference between series and sequences. So series, as we will see, are here to help us add numbers. So what is the problem? Let us do a simple addition problem. Let me give 3 numbers: A, B and C. If I ask you to add them, you will take a pen and a paper or a calculator and do the following:

1. You will enter the number A, then

2. You will add to it the number B, to get
A+B

3. And finally, you will add C to the previous result to get
A+B+C


So, if you are given one million numbers, you will still enter one by one to add all of them. A very simple operation, isn't it? Now what would happen if you were given infinitely many numbers? What would you do?