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The Maxima on-line user's manual

Algebra Calculator

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Log

Function: log (<x>) Represents the natural (base e) logarithm of <x>.

plot3d([ [(x/2*log(x))/(y^2*x*log(x/y)),[x,1E6,1E8],[y,2,30]] ]);

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 logs 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.

There are also some inexact matches for log. Try ?? log to see them.

(%o1)                                true
(%i2) 

Related Examples

log

1/0.02*(log(2400000)-...

Calculate

log

log((N/k1)**k1) < ...

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log

log(%e)*(x);

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log-tan

log(tan(lat/2+%pi/4));

Calculate

log

log((r+p+(1+a)*f)/(r+...

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log-numer

log(2000), numer;

Calculate

log-plot2d
plot2d(1/(x^2+1), [x, -2*log(2),2*log(2)]);

plot2d(1/(x^2+1), [x,...

Calculate

log

log(x-2);

Calculate

log-plot2d-sin
plot2d(log(x)*sin(x),[x,0,20]);

plot2d(log(x)*sin(x),...

Calculate

log

log(66);

Calculate