Getting Started 9
8300GETM.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 11:06 AM Printed: 02/19/01 11:06
AM Page 9 of 18
Take a 20 cm. × 25 cm. sheet of paper and cut X × X squares from two corners.
Cut X × 12.5 cm. rectangles from the other two corners as shown in the
diagram below. Fold the paper into a box with a lid. What value of X would
give your box the maximum volume V? Use the table and graphs to determine
the solution.
Begin by defining a function that describes the
v
olume of the box.
From the diagram: 2X + A = 20
2X + 2B = 25
V = A B X
Substituting: V = (20 N 2X) (25à2 N X) X
1. Press o to display the Y= editor, which is
where you define functions for tables and
graphing.
2. Press £ 20 ¹ 2 „ ¤ £ 25 ¥ 2 ¹
„ ¤ „ Í to define the
volume function as Y1 in terms of X.
„ lets you enter X quickly, without
having to press ƒ. The highlighted =
sign indicates that Y1 is selected.
Defining a Function: Box with Lid20 A
X
X B X B
25