Written by Sunny Yoon

The spreadsheet can be used to display the graph of parametric equations. One way is to place an initial value of the parameter t in cell A1 and increment t in the A column. Put the formula for the x-coordinate, in B1 and the y-coordinate in C1. Fill down to get the appropriate range of t and then graph .

Now, I'm going to try this parametric equation from Assignment 10. It is problem #4.

Here's how the graph looks like.

This is what I have done using Excel.


It didn't give me a perfect shape of a half circle like the one from the graphing calculator because I didn't let my t go on forever. Since t stopped at 39, that's how far the graph went. However, if you imagine that t was going on forever, it is easy to see how the graph will reach (-1, 0) in the end.


Now, let's try this parametric equation.


Here's the graph as t goes till 39.


As t goes from 0 to 39, x goes from 1 to 40 while y goes from -1 to 77 and it makes a linear line.

Here's my spreadsheet.


This time, I was able to represent the parametric equation exactly like the one using the Graphing Calculator.

I'm going to use another parametric equation. The equation derived from cubic equation which is a lot harder to graph in normal graphing calculators. eaq

Putting the equation in parametric form makes it a lot easier to graph. Let y = tx cross the curve at (0,0) and at (x,y). Then using substitution, you should get


Here's the graph of the parametric equation above as t goes from 0 to 39.


Here's what I have achieved using the spreadsheet.


Although both graphs have a curve shape, it is harder to see the exact shape on the spreadsheet. Unfortunately, the spreadsheet cannot graph the numbers in between integers. For the spreadsheet, as t goes from 0 to 39, it only looks at the integers 0 to 39 while the Graphing Calculator will use the real numbers in between two integers when graphing.


when a = 1, b = 2

Here's the graph.


Here's how it looks like in spreadsheet.




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