Paul's Online Notes
Paul's Online Notes
Home / Algebra / Graphing and Functions / Graphing
Show Mobile Notice Show All Notes Hide All Notes
Mobile Notice
You appear to be on a device with a "narrow" screen width (i.e. you are probably on a mobile phone). Due to the nature of the mathematics on this site it is best viewed in landscape mode. If your device is not in landscape mode many of the equations will run off the side of your device (you should be able to scroll/swipe to see them) and some of the menu items will be cut off due to the narrow screen width.

Section 3.1 : Graphing

2. Construct a table of at least 4 ordered pairs of points on the graph of the following equation and use the ordered pairs from the table to sketch the graph of the equation.

\[y = 1 - {x^2}\]

Show All Steps Hide All Steps

Hint : If you don’t know what the graph of a given equation is it can be very difficult to determine a good selection of values of \(x\) to use to construct the table. For this equation try a selection of at least a couple of points to either side of zero (maybe even including zero).
Start Solution

It is always a little difficult to know just what a good selection of values of \(x\) to use to determine the ordered pairs we will use to sketch the graph of an equation if you don’t know just what the graph looks like. Eventually you’ll do enough problems that you’ll start to develop some intuition on just what good values to try are for many equations.

For this equation a selection of points on either side of zero should be sufficient to get an idea of what the graph of this equation looks like. We’ll also include zero for no other reason that it will give an extra point on the graph.

Here is the table of points we’ll use for this problem.

\(x\) \(y\) \(\left( {x,y} \right)\)
-4 -15 \(\left( { - 4, - 15} \right)\)
-2 -3 \(\left( { - 2, - 3} \right)\)
0 1 \(\left( {0,1} \right)\)
2 -3 \(\left( {2, - 3} \right)\)
4 -15 \(\left( {4, - 15} \right)\)

We’ll leave the actual computations to you to verify but recall that all we do is take the \(x\) and plug it into the equation to determine the corresponding \(y\) value and then form the ordered pair for the \(x\) and its corresponding \(y\) value.

Show Step 2

Here is a sketch of the equation.