HP 15c - Manual (Page 142)

142 Section 4: Using Matrix Operations
142
Example: Use the optimization program to find the dimensions of the box of largest volume
with the sum of the length and girth (perimeter of cross section) equaling 100 centimeters.
For this problem
l + (2h + 2w) = 100
v = whl
v(w,h) = wh(100－2h－2w)
= 100wh － 2wh
2
－ 2hw
2






 
 
 
) 2 50 ( 2
) 2 50 ( 2
) , (
h w w
w h h
h w v .
The solution should satisfy w + h < 50, w > 0, and h > 0.
First enter a subroutine to calculate the gradient and the volume.
Keystrokes Display
´bE 120-42,21,15 Function subroutine.
lmA 121-45,23,11
´mE 122-42,23,15
´>1 123-42,16, 1
´UlA
´U 124u 45 11
O.2 125- 44 .2 Stores w in R
.2
.
OE 126- 44 15 Stores w in e
2
.
lA 127- 45 11
O.3 128- 44 .3 Stores h in R
.3
.
´>1 129-42,16, 1
OE 130- 44 15 Stores h in e
1
.
+ 131- 40
5 132- 5
0 133- 0
- 134- 30
” 135- 16
2 136- 2
* 137- 20 Calculates l = 2(50 − h − w).
´X.2 138-42, 4,.2 Stores l in R
.2
.
O*.3 139-44,20,.3 Stores wh in R
.3
.
l.2 140- 45 .2
l>E 141-45,16,15
´<E 142-42,26,15
* 143- 20