I =∫<0 inferior, π superior>xf(sinx)dx
=∫<π inferior, 0 superior>;(π-t)f [sin( π-t)]
=∫& lt; inferior 0, superior π& gt (π-t)f(sint)dt
=π∫& lt; superior π>f(Sint)dt-∫< inferior 0, superior π>tf(sint)dt
=π∫< inferior 0, superior π>f (sinx)dx - I p>
I = (π/2) ∫