看图,求dx,

看图,求dx,
看图,求dx,

看图,求dx,
∫√1-ln^2(x) d(lnx)然后自己解

∫<1,e>[√(1-ln²x)/x]dx
=∫<1,e>[√(1-ln²x)]d(lnx)
=∫<1,e>[√(1-t²)]dt(设t=lnx)
=arcsint|<1,e>
=arcsin(lnx)|<1,e>
arcsin(lne)-arcsin(ln1)
=arcsin(1)-arcsin(0)
=π/2-0
=π/2