Texas Instruments TI-89 Guide Book

Chapter 23: Activities 391
23ACTS.DOC TI-89/TI-92 Plus: Activities (English) Susan Gullord Revised: 02/23/01 1:24 PM Printed: 02/23/01 2:20 PM Page 391 of 26
Perform the following steps to solve the problem analytically on the
Home screen.
1. Solve for
x
and
y
in terms of
v
.
Enter:
solve(d(sa(x,y,v),x)=0 and
d(sa(x,y,v),y)=0,{x,y})
2. Find the minimum surface area
when the value of
v
equals 300.
Enter:
300
!
v
Enter:
sa(v^(1/3), v^(1/3),v)
Finding the
Minimum Surface
Area Analytically
Hint: Press
¸
to obtain
the exact result in symbolic
form. Press
¥¸
to
obtain the approximate
result in decimal form.

Texas Instruments TI-89 Specifications

General

Display size (HxV)	100 x 160 mm
Memory type	639K FLASH ROM, 188K bytes RAM
Compatible operating systems	Operating System 2.09
Battery type	AAA