Hello;
I was going to make a bug entry on this, but thought to first check with the experts here, as I have a feeling I am missing something basic or making some mistake, or overlooking something as I am newbie in SageMath and Maxima as well.
I am getting number of wrong antiderivatives from Sagemath intergate, using default algorithm (which should be Maxima), compared to using Maxima itself for same integral.
Using Maxima (and making sure to set domain to complex first), Maxima returns unevaluated for the same command, which is actually is the correct result, since these integrals are supposed to be non integrable and meant to test to see if CAS can determine this. However, sagemath, does return an antiderivative from Maxima.
Could someone please explain how sagemath managed to return such results, and from where it obtained it since Maxima itself does not return this result? In addition, I verified the SageMath result, and they all fail the verification I did.
Here are few examples of many I have:
Example 1
SageMath version 8.3.rc1, Release Date: 2018-07-14
sage: var('x e a b f c d m');
sage: integrate ((d*sin (f*x + e) + c)^(3/2)*(b*sin (f*x + e) + a)^m, x)
1/9*(c^3*sin(9/2*f*x + 9/2*e) - 3*c^3*sin(3/2*f*x + 3/2*e))*2^(-m - 5/2)/f
The above is clearly wrong, since the anti dropped/missing the parameters d,a,b
in the integrand.
in Maxima
Maxima 5.41.0 http://maxima.sourceforge.net
using Lisp ECL 16.1.2
(%i1) domain:complex$
(%i2) domain;
(%o2) complex
(%i3) integrate ((d*sin (f*x + e) + c)^(3/2)*(b*sin (f*x + e) + a)^m, x);
/
[ m 3/2
(%o3) I (b sin(f x + e) + a) (d sin(f x + e) + c) dx
]
/
Example 2
sage: integrate(sqrt(d*sin (f*x + e) + c)*(b*sin (f*x + e) + a)^m, x,algorithm="maxima")
1/3*(c*sin(3/2*f*x + 3/2*e) - 3*c*sin(1/2*f*x + 1/2*e))*2^(-m - 3/2)/f
The above is clearly wrong, since the anti dropped/missing the parameters d,a,b
in the integrand.
Using Maxima
(%i7) integrate (sqrt (d*sin (f*x + e) + c)*(b*sin (f*x + e) + a)^m, x);
/
[ m
(%o7) I (b sin(f x + e) + a) sqrt(d sin(f x + e) + c) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 3
sage: integrate (x*sqrt (cos (b*x + a)), x,algorithm="maxima")
1/840*(70*sqrt(2)*a*(sin(3/2*b*x + 3/2*a) - 3*sin(1/2*b*x + 1/2*a)) - sqrt(2)*(15*sin(7/2*b*x + 7/2*a) - 21*sin(5/2*b*x + 5/2*a) - 35*sin(3/2*b*x + 3/2*a) + 105*sin(1/2*b*x + 1/2*a)))/b^2
The above result did not verify by differentiating the antiderivative.
Using Maxima
(%i9) integrate (x*sqrt (cos (b*x + a)), x);
/
[
(%o9) I x sqrt(cos(b x + a)) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.
example 4
sage: integrate(x*cos(b*x + a)^(3/2), x, algorithm="maxima")
1/349920*(243*sqrt(2)*a*(3*sin(15/2*b*x + 15/2*a) + 5*sin(9/2*b*x + 9/2*a) - 30*sin(3/2*b*x + 3/2*a)) - 20*sqrt(2)*(2*(81*(b*x + a)^2 - 8)*cos(9/2*b*x + 9/2*a) - 162*(9*(b*x + a)^2 - 8)*cos(3/2*b*x + 3/2*a) + 9*(27*(b*x + a)^3 - 8*b*x - 8*a)*sin(9/2*b*x + 9/2*a) - 243*(3*(b*x + a)^3 - 8*b*x - 8*a)*sin(3/2*b*x + 3/2*a)))/b^2
The above result did not verify by differentiating the antiderivative.
Using Maxima
(%i10) integrate(x*cos(b*x + a)^(3/2), x);
/
[ 3/2
(%o10) I x cos(b x + a) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 5
sage: integrate(cos (x)^(3/2)/x^3, x, algorithm="maxima")
-9/512*sqrt(2)*(25*gamma(-2, 15/2*I*x) + 9*gamma(-2, 9/2*I*x) - 2*gamma(-2, 3/2*I*x) - 2*gamma(-2, -3/2*I*x) + 9*gamma(-2, -9/2*I*x) + 25*gamma(-2, -15/2*I*x))
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i11) integrate (cos (x)^(3/2)/x^3, x);
/ 3/2
[ cos(x)
(%o11) I --------- dx
] 3
/ x
The above is the correct result, since this integral is supposed to be non integrable.
Example 6
sage: integrate(cos(d*x + c)^(7/3)/sqrt(b*cos(d*x + c) + a), x,algorithm="maxima")
1/6366178138320*2^(1/6)*(61213251330*cos(13/2*d*x + 13/2*c) - 72342933390*cos(11/2*d*x + 11/2*c) - 82321269030*cos(29/6*d*x + 29/6*c) + 140430400110*cos(17/6*d*x + 17/6*c) - 217028800170*cos(11/6*d*x + 11/6*c) - 341045257410*cos(7/6*d*x + 7/6*c) + 23405066685*sin(17/2*d*x + 17/2*c) - 26525742243*sin(15/2*d*x + 15/2*c) - 29113619535*sin(41/6*d*x + 41/6*c) + 41160634515*sin(29/6*d*x + 29/6*c) - 44209570405*sin(9/2*d*x + 9/2*c) - 51898191345*sin(23/6*d*x + 23/6*c) + 56840876235*sin(7/2*d*x + 7/2*c) - 62824126365*sin(19/6*d*x + 19/6*c) + 70215200055*sin(17/6*d*x + 17/6*c) + 1193658400935*sin(1/6*d*x + 1/6*c))/(a*d)
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i12) integrate (cos (d*x + c)^(7/3)/sqrt (b*cos (d*x + c) + a), x);
/ 7/3
[ cos(d x + c)
(%o12) I ------------------------ dx
] sqrt(b cos(d x + c) + a)
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 7
sage: integrate(cos(d*x + c)^(2/3)/sqrt(b*cos(d*x + c) + a), x,algorithm="maxima")
-1/54264*2^(5/6)*(1071*cos(19/6*d*x + 19/6*c) + 1197*cos(17/6*d*x + 17/6*c) - 2261*cos(3/2*d*x + 3/2*c) - 2907*cos(7/6*d*x + 7/6*c) + 6783*cos(1/2*d*x + 1/2*c) + 20349*cos(1/6*d*x + 1/6*c))/(a*d)
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i13) integrate (cos (d*x + c)^(2/3)/sqrt (b*cos (d*x + c) + a), x);
/ 2/3
[ cos(d x + c)
(%o13) I ------------------------ dx
] sqrt(b cos(d x + c) + a)
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 8
sage: var('B A f x e b a c m')
(B, A, f, x, e, b, a, c, m)
sage: integrate((B*cos(f*x+e)+A)*(b*cos(f*x+e)+a)^(3/2)*(c*cos(f*x+e))^m,x)
1/3465*(385*(a^3*c^m*sin(9/2*f*x + 9/2*e) - 3*a^3*c^m*sin(3/2*f*x + 3/2*e))*2^(-m - 5/2)*A + 4*(231*a^3*sin(15/2*f*x + 15/2*e) + 630*a^3*sin(11/2*f*x + 11/2*e) - 770*a^3*sin(9/2*f*x + 9/2*e) + 495*a^3*sin(7/2*f*x + 7/2*e) - 2079*a^3*sin(5/2*f*x + 5/2*e) + 1155*a^3*sin(3/2*f*x + 3/2*e))*2^(-m - 13/2)*B)/f
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i15) integrate((B*cos(f*x+e)+A)*(b*cos(f*x+e)+a)^(3/2)*(c*cos(f*x+e))^m,x);
/
[ m 3/2
(%o15) I (c cos(f x + e)) (B cos(f x + e) + A) (b cos(f x + e) + a) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 9
sage: integrate((B*cos(f*x+e)+A)*sqrt(b*cos(f*x+e)+a)*(c*cos(f*x+e))^m,x)
1/315*(105*(a*c^m*sin(3/2*f*x + 3/2*e) - 3*a*c^m*sin(1/2*f*x + 1/2*e))*2^(-m - 3/2)*A + (35*a*sin(9/2*f*x + 9/2*e) - 90*a*sin(7/2*f*x + 7/2*e) + 189*a*sin(5/2*f*x + 5/2*e) - 315*a*sin(3/2*f*x + 3/2*e) + 315*a*sin(1/2*f*x + 1/2*e))*2^(-m - 7/2)*B)/f
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i16) integrate((B*cos(f*x+e)+A)*sqrt(b*cos(f*x+e)+a)*(c*cos(f*x+e))^m,x);
/
[ m
(%o16) I (c cos(f x + e)) (B cos(f x + e) + A) sqrt(b cos(f x + e) + a) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 10
sage: integrate((B*cos(f*x+e)+A)*(b*cos(f*x+e)+a)^(3/2)*(c*sec(f*x+e))^m,x)
-1/2520*sqrt(2)*(35*2^m*A^3*a*sin(9/2*f*x + 9/2*e) + 630*(A^3*B - A^3*a)*2^m*log(cos(1/2*f*x + 1/2*e)^2 + sin(1/2*f*x + 1/2*e)^2 + 2*sin(1/2*f*x + 1/2*e) + 1) - 630*(A^3*B - A^3*a)*2^m*log(cos(1/2*f*x + 1/2*e)^2 + sin(1/2*f*x + 1/2*e)^2 - 2*sin(1/2*f*x + 1/2*e) + 1) + 45*(2*A^3*B - A^3*a)*2^m*sin(7/2*f*x + 7/2*e) - 63*(2*A^3*B - 3*A^3*a)*2^m*sin(5/2*f*x + 5/2*e) + 105*(4*A^3*B - 5*A^3*a)*2^m*sin(3/2*f*x + 3/2*e) - 630*(4*A^3*B - 3*A^3*a)*2^m*sin(1/2*f*x + 1/2*e))/f
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i17) integrate((B*cos(f*x+e)+A)*(b*cos(f*x+e)+a)^(3/2)*(c*sec(f*x+e))^m,x);
/
[ 3/2 m
(%o17) I (B cos(f x + e) + A) (b cos(f x + e) + a) (c sec(f x + e)) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.
Example 11
sage: integrate((B*cos(f*x+e)+A)*sqrt(b*cos(f*x+e)+a)*(c*sec(f*x+e))^m,x)
1/40*(20*sqrt(2)*(2^m*a*c^m*log(cos(1/2*f*x + 1/2*e)^2 + sin(1/2*f*x + 1/2*e)^2 + 2*sin(1/2*f*x + 1/2*e) + 1) - 2^m*a*c^m*log(cos(1/2*f*x + 1/2*e)^2 + sin(1/2*f*x + 1/2*e)^2 - 2*sin(1/2*f*x + 1/2*e) + 1) - 2^(m + 1)*a*c^m*sin(1/2*f*x + 1/2*e))*A + sqrt(2)*(5*2^(m + 2)*a*log(cos(1/2*f*x + 1/2*e)^2 + sin(1/2*f*x + 1/2*e)^2 + 2*sin(1/2*f*x + 1/2*e) + 1) - 5*2^(m + 2)*a*log(cos(1/2*f*x + 1/2*e)^2 + sin(1/2*f*x + 1/2*e)^2 - 2*sin(1/2*f*x + 1/2*e) + 1) - 2^(m + 1)*a*sin(5/2*f*x + 5/2*e) + 5*2^(m + 1)*a*sin(3/2*f*x + 3/2*e) - 15*2^(m + 2)*a*sin(1/2*f*x + 1/2*e))*B)/f
The above result did not verify by differentiating the antiderivative.
Maxima:
(%i18) integrate((B*cos(f*x+e)+A)*sqrt(b*cos(f*x+e)+a)*(c*sec(f*x+e))^m,x);
/
[ m
(%o18) I (B cos(f x + e) + A) sqrt(b cos(f x + e) + a) (c sec(f x + e)) dx
]
/
The above is the correct result, since this integral is supposed to be non integrable.