Graphics Programs Reference
In-Depth Information
r = sqrt(xˆ2 + yˆ2);
theta = atan2(y,x);
If you type
polarcoordinates(3,4)
, only the first output argument is re-
turned and stored in
ans
; in this case, the answer is
5
. To see bothoutputs,
you must assign them to variables enclosed in square brackets:
>> [r, theta] = polarcoordinates(3,4)
r=
5
theta =
0.9273
By typing
r = polarcoordinates(3,4)
you can assign the first output ar-
gument to the variable
r
, but you cannot get only the second output argument;
typing
theta = polarcoordinates(3,4)
will still assign the first output,
5
,to
theta
.
Complex Arithmetic
MATLAB does most of its computatio
ns
using
complexnumbers
, that is, num-
bers of the form
a
+
bi
, where
i
=
√
−
1 and
a
and
b
are real numbers. The
complex number
i
is represented as
i
in MATLAB. Although you may never
have occasion to enter a complex number in a MATLAB session, MATLAB
often produces an answer involving a complex number. For example, many
polynomials withreal coefficients have complex roots:
>> solve('xˆ2 + 2*x+2=0')
ans =
[ -1+i]
[ -1-i]
Bothroots of this quadratic equation are complex numbers, expressed in
terms of the number
i
. Some common functions also return complex values
for certain values of the argument. For example,
>> log(-1)
ans =
0 + 3.1416i
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