Graphics Programs Reference
In-Depth Information
ax
b
fits the following datainthe least-squares
14.Determine
a
and
b
so that
f
(
x
)
=
sense.
x
0
.
5
1
.
0
1
.
5
2
.
0
2
.
5
y
0
.
49
1
.
60
3
.
36
6
.
44
10
.
16
axe
bx
to the data and compute the standard deviation.
15. Fit the function
f
(
x
)
=
x
0
.
5
1
.
0
1
.
5
2
.
0
2
.
5
y
0
.
541
0
.
398
0
.
232
0
.
106
0
.
052
16.
The intensity of radiation of a radioactivesubstance was measuredathalf-year
intervals. The results were:
t
(years)
0
0
.
5
1
1
.
5
2
2
.
5
γ
1
.
000
0
.
994
0
.
990
0
.
985
0
.
979
0
.
977
t
(years)
3
3
.
5
4
4
.
5
5
5
.
5
γ
0
.
972
0
.
969
0
.
967
0
.
960
0
.
956
0
.
952
where
is the relative intensity of radiation. Knowing that radioactivitydecays
exponentiallywith time:
γ
ae
−
bt
, estimate the radioactivehalf-life of the
γ
(
t
)
=
substance.
MATLAB Functions
y = interp1(xData,xData,x,method)
returns the value of the interpolant
y
at
point
x
according to the
method
specified:
method = 'linear'
uses linear
interpolationbetween adjacent datapoints (this is the default);
method =
'spline'
carries outcubicspline interpolation. If
x
is an array,
y
iscomputed
forall elements of
x
.
a = polyfit(xData,yData,m)
returns the coefficients
a
of apolynomialofdegree
m
that fits the datapoints in the least-squares sense.
y = polyval(a,x)
evaluates apolynomial definedbyits coefficients
a
at point
x
.
If
x
is an array,
y
iscomputed forall elements of
x
.
s = std(x)
returns the standarddeviation of the elements of array
x
. If
x
is amatrix,
s
iscomputed for each column of
x
.
xbar = mean(x)
computes the mean value of the elements of
x
. If
x
is amatrix,
xbar
iscomputed for each column of
x
.
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