HP 40gs User Manual page 117

hp40g+.book Page 13 Friday, December 9, 2005 1:03 AM
To define your
own fit
Statistics aplet
Fit model Meaning (Continued)
Quadratic Fits to a quadratic curve,
y = ax
three points.
Cubic Fits to a cubic curve,
y = ax
four points.
Logistic Fits to a logistic curve,
y
where L is the saturation value for
growth. You can store a positive
real value in L, or—if L=0—let L
be computed automatically.
Exponent Fits to an exponent curve,
y
Trigonometric Fits to a trigonometric curve,
y
at least three points.
User Defined Define your own expression (in
Symbolic view.)
1. In Numeric view, make sure
2. Display the Symbolic view.
3. Highlight the Fit expression (Fit1, etc.) for the
desired data set.
4. Type in an expression and press
The independent variable must be X, and the
expression must not contain any unknown variables.
×
1.5 cos x
Example:
This automatically changes the Fit type (S1FIT, etc.) in
the Symbolic Setup view to User Defined.
2
+bx+c. Needs at least
3 2
+bx +cx+d. Needs at least
L
------------------------- -
=
,
– ( )
bx
1 + ae
x
= ab
.
⋅ ( )
= a sin bx + c + d
. Needs
is set.
.
×
+ 0.3 sin x
.
10-13