Maxima Function
log (x)
Represents the natural (base e) logarithm of x.
Maxima does not have a built-in function for the base 10 logarithm or other bases.
log10(x) := log(x) / log(10)
is a useful definition.
Simplification and evaluation of logarithms is governed by several global flags:
logexpand
- causes log(a^b)
to become b*log(a)
.
If it is set to all
, log(a*b)
will also simplify to log(a)+log(b)
.
If it is set to super
, then log(a/b)
will also simplify to log(a)-log(b)
for rational
numbers a/b
, a#1
. (log(1/b)
, for b
integer, always simplifies.) If
it is set to false
, all of these simplifications will be turned off.
logsimp
- if false
then no simplification of %e
to a power
containing log
's is done.
lognumer
- if true
then negative floating point arguments to
log
will always be converted to their absolute value before the log
is
taken. If numer
is also true
, then negative integer arguments to log
will also be converted to their absolute value.
lognegint
- if true
implements the rule log(-n)
->
log(n)+%i*%pi
for n
a positive integer.
%e_to_numlog
- when true
, r
some rational number, and
x
some expression, %e^(r*log(x))
will be simplified into
x^r
. It should be noted that the radcan
command also
does this transformation, and more complicated transformations of this ilk as well.
The logcontract
command "contracts" expressions containing log
.