Sketch the graph of
y = ( x -1)2 - 4 .
Solution
Now, it is a parabola .Though, we haven't gotten that far yet and thus we will have to select some values of x, plug them in and calculate the y values.
As indicated earlier, it helps to have an idea of what this graph is liable to look as while picking values of x. Thus, don't worry at this instance why we select the values which we did. After the next chapter you would also be capable to select these values of x.
Following is a table of values for this equation.
|
x
|
y
|
( x, y )
|
|
-2
|
5
|
( -2, 5)
|
|
-1
|
0
|
( -1, 0)
|
|
0
|
-3
|
(0, -3)
|
|
1
|
-4
|
(1, -4)
|
|
2
|
-3
|
( 2, -3)
|
|
3
|
0
|
(3, 0)
|
|
4
|
5
|
( 4, 5)
|
Let's check the first one .For the first one we only plug x' -2 into the equation and compute y.
y = ( -2 -1)2 - 4
= ( -3)2 - 4
=9 - 4
= 5
Given is the graph of this equation.
Notice that while we set up the axis system in this instance, we only set up as much as we required. For instance, since we didn't go past -2 along our computations we didn't go much past that along our axis system.
Also, notice that we utilized a different scale on each of the axes. Along the horizontal axis we incremented by 1's whereas on the vertical axis we incremented through 2. It will frequently be done in order to make the sketching easier.