TopA graph is basically a physical representation of data which can be easily understood by anyone. It is made from Combination of different points between coordinates which are called vertex or nodes. A graph can be of any type like: polar graph, straight line graph, double line graph, exponential curve graph, waterfall graph, ladder graph, curvilinear graph, etc. Now Question arises how to analyze a graph, for this let us go through a small example.
Straight line graph has been drawn for understanding how to analyze a Graph:
In above figure, we have two axis like X - axis and Y - axis. On the X - axis we have the scale of one. The Numbers 1, 2, 3, 4 are marked, similarly on left side of origin we have negative X- axis where we have numbers marked as -1, -2 , -3, -4. On Y- axis we have 1, 2, 3, 4 of scale 1. Similarly at the bottom Negative Y - axis we have -1 and -2 numbers marked.
On the graph we can see a Straight Line crossing from X - axis to perpendicular Y - axis. Points where line meets have been indicated by a small cross (X). Each cross marked on straight line is called coordinates. So, on given line we have four coordinates like (-3, 0), (-2, 1), (-1, 2) and (0, 3). Coordinate is defined by the 'x' point on X - axis and y- point on Y- axis. So we have coordinate as (x, y). So Point on x- axis -3 and point on y- axis as 0 forms the coordinate as (-3, 0).
We can go through this small example and learn how to draw a graph and how to analyze a straight line graph.