Draw the graph of the identity function `f:RtoR:f(x)=x` for all `x""inR`.

Explanation

Here `f(x)=x` for all `x""inR`.
We may prepare its table as under.

On a graph paper, we draw X' OX and YOY' as the x-axis and the y-axis respectively.
We take 10 small divisions =1 unit.
Now, on this graph paper, we plot the points
`A(-2,-2),B(-1,-1),O(0,0),C(1,1),D(2,2)andE(3,3)`
Join these points successively to obtain the straight line ABOCDE as the required graph line, given below.

Let, c be fixed real number.
Then, the function `f:RtoR:f(x)=c` for all `x""inR` is called the the constant function.
For the constant function f(x)=c for all `x""inR`, we have dom (f) = R and range `(f)={c}`