TITLE: Why is $\int_{0}^{1}x^x(1-x)^{2-x}\sin(x\pi)dx=\int_{0}^{1}x^{1+x}(1-x)^{1-x}\sin(x\pi)dx?$
QUESTION [8 upvotes]: I don't know why these two integrals yield the same results. 
$$\int_{0}^{1}x^x(1-x)^{2-x}\sin(x\pi)dx=\int_{0}^{1}x^{1+x}(1-x)^{1-x}\sin(x\pi)dx$$
Any hints, clues and ideas how to go about dealing these integrals(showing that they are the same and determine the closed form)?
$$\int_{0}^{1}x^x(1-x)^{2-x}\sin(x\pi)dx=\int_{0}^{1}x^{1+x}(1-x)^{1-x}\sin(x\pi)dx$$I know it is similar to the sophere's dream integral.  I think you can possible use integration by parts. Because there are three functions are involved applying by parts it would be very long.
I try to make a substitution of $u=1-x$
$$-\int_{0}^{1}u^{1+u}(1-u)^{1-u}\sin((u+1)\pi)du$$
Q: show that they are the same and evaluate its closed form.
Edited
$$\int_{0}^{1}u^{1+u}(1-u)^{1-u}\sin(u\pi)du$$

Let try and applying by parts
$u=x^x(1-x)^{2-x}$
$du=x^x(1-x)^{2-x}\ln{x\over 2-x}dx$
$v=-{\cos{(x\pi)}\over \pi}$
$$=-{1\over \pi}x^x(1-x)^{2-x}\cos{(x\pi)}+{1\over \pi}\int_{0}^{1}x^x(1-x)^{2-x}\cos{(x\pi)}\ln{x\over 2-x}dx$$
This looked more complicate than before, so ideally, no, it is not a good way of tackling this problem.

REPLY [7 votes]: In the second integral, make the substitution $v=1-x$, so that $x=1-v$ and $dx = -dv$.  We get
$$\int_0^1 x^{1+x}(1-x)^{1-x}\sin(x\pi) \; dx = \int_1^0 (1-v)^{1+(1-v)} v^v \sin((1-v)\pi) \; (-dv).$$
The minus sign on $dv$ reverses the order of integration, and we have the identity $\sin(\pi -A) = \sin A$, so the above is
$$\int_0^1 (1-v)^{2-v}v^v \sin(v\pi) \; dv,$$
but since $v$ is a dummy variable, we can change it to $x$ and we have the first integral.