∫(1到4) lnx/√x
=∫(1到4)lnx d(2√x)
=lnx*2√x-∫(1到4) 2√x d(lnx)
=2√xlnx-4√x (1到4)
=(2√4*ln4-4√4)-(2√1*ln1-4√1)
=8ln2-8-0+4
=8ln2-4