Expert: Josh - 4/10/2010

Question
plz tell about graph that what is graph and what purpose it from begining thanks

Answer
Aima,

This question is too broad in scope to cover in a single question.
The answer varies depending on your education background (i.e., what school level you are in).

If you are in primary or high school, a "graph" is a plot (usually in two-dimension, such as a line graph, but there are other types) which commonly shows the relationship between an independent variable and a dependent variable.

The simplest example we can consider is a straight line equation of the form y=mx+b. Here, "x" is considered the independent (also called "unknown") variable, whereas "y" is considered the dependent variable. This means, as we adjust the value of "x", the value of "y" follows and changes according to the equation.

Often, you will be asked to tabulate the function. i.e., produce something like
-------------------------------
x | -2 | -1 | 0 | +1 | +2 |...
-------------------------------
y | -3 | -1 | 1 | +3 | +5 |...
-------------------------------
to show the relationship between the input "x" and output "y". From these (x,y) points, you plot these coordinates on the x-y plane and join the dots to produce a graph.

As I said, there is too much to reasonably cover in a single question. To find out more, look up a tutorial on "graphs" using a search engine. You might want to see different types of graphs and see what a parabola, or polynomial looks like in a graphical representation.

If you are doing more advanced maths, a "graph" fundamentally consists of "branches" and "nodes". Depending on what objective you are trying to achieve, these nodes and branches carry different meaning. They may, for instance, represent a road network. In this case, the links may show the cost of traveling between point A and point B. The goal might be to find the shortest path between two points (nodes). Again, check out web resources if you want to learn more about this vast topic.