Filter
Top Products
EL-9900 Graphing Calculator
12-3
Enter
Y1 =
√
3 - 3(x - 3)
2
Y2 = Y1 - 2
Y3 = -Y1 -2
Graph an ellipse in rectangular mode. Solve the equation for y to put it in the
standard form.
Example
Graph the ellipse 3(x -3)
2
+ (y + 2)
2
= 3
Graphing Ellipses
The standard equation for an ellipse whose center is at the point (h, k) with major and
minor axes of length a and b is + = 1.
There is a problem entering this equation in the calculator graphing list for two reasons:
a) it is not a function, and only functions can be entered in the Y = list locations.
b) the functions entered in the Y = list locations must be in terms of x, not y.
To draw a graph of an ellipse, consider the “top” and “bottom” halves of the ellipse as two
different parts of the graph because each individual is a function. Solve the equation of the
ellipse for y and enter the two parts in two locations of the Y = list.
(x - h)
2
a
2
(y - k)
2
b
2
1
Solve the equation for y, completing
the square.
2
Turn off Y1 so that it will not graph.
Y= 3
(
-
)
—
VARS
ENTER
ENTER
ENTER
ENTER
VARS
—
—
3
A
3
1
2
2nd F
√
ENTER
(
)
3(x - 3)
2
+ (y + 2)
2
= 3
(y + 2)
2
= 3 - 3(x - 3)
2
y + 2 =
√
3 - 3(x - 3)
2
y =
√
3 - 3(x - 3)
2
- 2
+
+
1
—
2
Before
Starting
There may be differences in the results of calculations and graph plotting depending on the setting.
Return all settings to the default value and delete all data.
Set the zoom to the decimal window:
(
)
ENTER
A
ZOOM
7
ALPHA
NotesStep & Key Operation Display
2nd F
2nd F
X/
/T/n
x
2