Online Algebra Calculator
Many of users do not use powerful Maxima computer algebra system for systematic work, but for ad hoc algebraic calculations – equations, functions, matrixes, etc. only. To do this job, it is not useful to download the whole application from a web site.
Integrate_use_rootsof Calculator
-- Option variable: integrate_use_rootsof Default value: false
When integrate_use_rootsof is true and the denominator of a rational function cannot be factored, integrate returns the integral in a form which is a sum over the roots (not yet known) of the denominator.
For example, with integrate_use_rootsof set to false, integrate returns an unsolved integral of a rational function in noun form:
(%i1) integrate_use_rootsof: false$
(%i2) integrate (1/(1+x+x^5), x);
/ 2
[ x - 4 x + 5
I ------------ dx 2 x + 1
] 3 2 2 5 atan(-------)
/ x - x + 1 log(x + x + 1) sqrt(3)
(%o2) ----------------- - --------------- + ---------------
7 14 7 sqrt(3)Now we set the flag to be true and the unsolved part of the integral will be expressed as a summation over the roots of the denominator of the rational function:
(%i3) integrate_use_rootsof: true$
(%i4) integrate (1/(1+x+x^5), x);
==== 2
\ (%r4 - 4 %r4 + 5) log(x - %r4)
> -------------------------------
/ 2
==== 3 %r4 - 2 %r4
3 2
%r4 in rootsof(x - x + 1)
(%o4) ----------------------------------------------------------
72 x + 1 2 5 atan(-------) log(x + x + 1) sqrt(3) - --------------- + --------------- 14 7 sqrt(3)
Alternatively the user may compute the roots of the denominator separately, and then express the integrand in terms of these roots, e.g., 1/((x - a)*(x - b)*(x - c)) or 1/((x^2 - (a+b)*x + a*b)*(x - c)) if the denominator is a cubic polynomial. Sometimes this will help Maxima obtain a more useful result.
(%o1) true (%i2)