- Put the function table and coordinate grid on the board. (You can download and project the template spreadsheet above).
- Enter an appropriate number in the x column of the function table. Then enter a y value. Ask students where the point these two numbers describe would fall on the coordinate grid. Get someone to plot it with help from the class. Then plot it yourself (by hitting "enter" if using the projected spreadsheet)
- Repeat the above using numbers that form a straight line. Plot at least five points.
- Review with notes on the board: A point on a grid is identified by two coordinates: x (horizontal) and y (vertical).
- Erase the function table and write a simple linear equation in the equation box. Enter x values and let the class calculate the y value. You can demonstrate the algebraic method of writing the equation, plugging in the x value, and solving. Then plot the points forming a straight line. You can also enter some y values and then calculate the x values.
- Have students access the template on their computers. At first they may need to be given simple linear equations, but gradually they can make up their own. Each student should create at least 3 graphs. As they get more comfortable, encourage them to note the y intercepts and to change the slopes. (Exponents will create a curve)
Examples of progressively more complex graphed points and equations
At first, students might just want to practice entering coordinates for a while. This can be demonstrated if you have a projector or a SMART board.
It’s your judgment when they are ready to grapple with equations or the concept of a y intercept. In the graphs below we've started with y = x and then y = x + 3.
Computers tend to use the carat symbol “^” to indicate exponents, used here for y = x^2.
You can encourage students to play with Excel functions which include trigonometry functions plus a lot more! In the example below, we've used y = sin(x).