# Thread: setting the window to graph parametric equations

1. ## setting the window to graph parametric equations

I have a TI-84 Plus calculator and I want to understand how to set the window. I have some homework problems and the first window is given as follows for the problem sketch the curve C1 with parametric equations.
these are the equations for this problem:
x(t) = cost
y(t) = sint

0<= t <=2pi

Tmin = 0, Tmax = 2pi, Xmin = -2, Xmax = 2, Ymin = -2, and Ymax = 2 .
Does the number if frount of pi set the rest of the min's and max's?
For example if the range was 0<= t <= pi/2, would I put Tmin at 0
Tmax = pi/2, Xmin = -.5, Xmax = .5, Ymin = -.5, and Ymax = .5 or does it not work this way. I have the calculator in radians and parametric modes but I am not sure I will get the correct picture if the window is not set correctly. The problems seem to be easy, just draw the graph, show the orientation with an arrow (closcwise or counterclockwise) and fill in a table for t, x(t), and y(t). Anyway if someone could explain the window to me I would be ever so greatful!!!!!!!!!!!!!!!!
Thank you,
Keith Stevens 2. Originally Posted by kcsteven I have a TI-84 Plus calculator and I want to understand how to set the window. ...
these are the equations for this problem:
x(t) = cost
y(t) = sint

0<= t <=2pi

Tmin = 0, Tmax = 2pi, Xmin = -2, Xmax = 2, Ymin = -2, and Ymax = 2 .
...
Hello, Keith,

maybe I am too late, but perhaps this will help you in the future;

With Tmin and Tmax you set the limits of the domain of your parametric function. That means if you choose for a smaller Tmax you only get a part of the function's graph. For instance: Set Tmax=1 and look what will happen to your graph.
The most important value is tstep. The smaller tstep is the more exact the graph of the function is drawn, but the more time it takes to calculate the table and to draw the graph. For instance set tstep = .01 and watch the procedure of drawing.

With xmin, xmax, ymin and ymax you construct the frame around the picture which contains the graph of the function. For instance: Set xmin=-10, xmax=10, ymin=-10 and ymax=10. You'll get the same picture but very small because you have enlarged the frame by the factor 5.

So it is necessary to get a little bit experience to set the frame accurately. There is no connection between the domain of a function and the size of the window which shows the graph but one: It would be very convenient if you can see the most important parts of the graph.

One last remark: As you may know you find the table containing t, x(t) and y(t) under yellow+F5.

EB

equations, graph, parametric, setting, window 