HP 39gs Master Guide

(ii) Predict N for t = 15 hours.
In the
PLOT view, press up arrow to move the cursor onto the
curve of best fit. Now press
and enter the value 15. The
cursor will jump to the predicted value for x=15, which is
currently off screen.
Alternatively, change to the
HOME view and use the PREDY
function.
Result: 268 269 colonies.
1
(iii) Find t so that
N = N
0
.
2
Step 1. Find the values of
N
0
and k and store N into memory A
0
and k into memory K, so that it is un-necessary to re-type them.
See page 135 for instructions on finding the parameters from
the exponential fit curve.
Step 2. Switch to the Solve aplet and enter the equation to be solved.
Changing into the
NUM view, you should find the values of A
and
K already defined, so move the highlight to T and press
.
Result: Doubling time is 1.0536 hours.
306

HP 39gs Specifications

General

Type	Scientific
Form factor	Pocket
Product color	Gray
Internal memory	0.256 MB

Weight and Dimensions

Weight	249 g
Dimensions (WxDxH)	187 x 94 x 31 mm