Did you consider trying both? If you let u= ln(x), what is du? If you let u= sqrt(ln(x)), what is du? Which works?2) How would I use the substitution method to solve for (sqrt(lnx))/x? What would be my u? lnx or sqrt(lnx)?
Again, obvious substitutions are either u= 3x or u= cos(3x). What do you get for du if you try either of those?3) How would I use substitution to integrate sin(3x)e(cos3x) dx?
Any help with any of these is greatly appreciated. Even knowing where to start would be great. Thanks!