Wrong solution/output for differential equation
As the user rburing advised in the thread https://ask.sagemath.org/question/449... I'm opening this one now.
When running the following code, one obtains a wrong output:
y=function('y')(x)
desolve(diff(y)==4*y/x+x*sqrt(y),y,ics=[1,1]).factor()
The output is 1/4*x^4*(log(x) - 2)^2
instead of 1/4*x^4*(log(x) + 2)^2
. Mathematica however outputs both (by running DSolve[{D[y[x], x] == 4*y[x]/x + x*Sqrt[y[x]], y[1] == 1}, y[x], x]
).
The problem is specific to
maxima
:sympy
has another, distinct, failure.fricas
fails entirely.giac
gives an acceptable answer.You should follow the steps suggested in the documentation, possibly also reporting this bug against
maxima
.How do you "access" those answers? For example,
desolve(diff(y)==4*y/x+x*sqrt(y),y,ics=[1,1],algorithm="giac")
givesValueError: unknown algorithm giac
.giac("desolve([y'=4*y/x+x*sqrt(y),y(1)=1],y)").sage()
should give you[1/4*(ln(x) + 2)^2*e^(4*ln(x))]
.