Good morning, I computed the following integral using Integrate in version 12.2 and it gives the wrong result. Can you help me understand what I am doing wrong? Here is the integral:
Integrate[(
n (1 + n) (1 + 2 n) (3 +
2 n) (-HypergeometricPFQ[{1, 1, 1 - 2 n, 4 + 2 n}, {2, 3, 3}, 1] +
t HypergeometricPFQ[{1, 1, 1 - 2 n, 4 + 2 n}, {2, 3, 3}, t]) Log[
t])/(-1 + t), {t, 0, 1}, {u, 0, 1},
Assumptions -> n \[Element] Integers && n > 0]
the result is
-(1/6) n (1 + n) (1 + 2 n) (3 + 2 n) \[Pi]^2 HypergeometricPFQ[{1, 1,
1 - 2 n, 4 + 2 n}, {2, 3, 3}, 1]
For instance, this result is $-\frac{10 \pi ^2}{3} $ for $n=1$. However if I set $n=1$ inside Integrate or use NIntegrate i get $-17.5$, which is the correct result. Why is there such a difference? Here is the code
NIntegrate[((
n (1 + n) (1 + 2 n) (3 +
2 n) (-HypergeometricPFQ[{1, 1, 1 - 2 n, 4 + 2 n}, {2, 3, 3},
1] + t HypergeometricPFQ[{1, 1, 1 - 2 n, 4 + 2 n}, {2, 3, 3},
t]) Log[t])/(-1 + t)) /. n -> 1, {t, 0, 1}, {u, 0, 1}]
and
Integrate[(
n (1 + n) (1 + 2 n) (3 +
2 n) (-HypergeometricPFQ[{1, 1, 1 - 2 n, 4 + 2 n}, {2, 3, 3},
1] + t HypergeometricPFQ[{1, 1, 1 - 2 n, 4 + 2 n}, {2, 3, 3},
t]) Log[t])/(-1 + t) /. n -> 1, {t, 0, 1}, {u, 0, 1},
Assumptions -> n \[Element] Integers && n > 0]
Thank you for your help.
-35/2
in MM 12.3.1 for Mac OS (ARM). $\endgroup$"12.2.0 for Mac OS X x86 (64-bit) (December 12, 2020)"
as well as in V12.3.1. $\endgroup$