# Tutor profile: Michael D.

## Questions

### Subject: Java Programming

I wrote a tester class that is supposed to find data from a text file but every time i type in the files name it throws a file not found exception.

well for this one it would help to see your code so if you could copy and paste it into the chat that would help me out. most likely the problem is that you are just typing the file name example.txt. if this is the case it will only find that file if it is in the same folder as the program that is looking for it. so you can put it in the same folder as your tester class or type in its fully qualified name c:\"insert full path here"\example.txt

### Subject: Calculus

integration by parts is slipping me up whats the formula for it and please expand on what each part means.

so for example we will use the integral (x* sin(x) *dx) so first you want to check if usub is usable in this situation but it is not so the next best thing to try is integration by parts because it will simplify the integral.so the formula is u*v -integral (v* du) the term u will get simpler so if one of your terms is x thats the best to set for u. so u= x in this example . du being the derivative of u so du= 1 dx you take what is left in the integral and set it = to dv so in this case dv= sin(x) dx knowing this we integrate to find v= -cos(x) now leaving us with x*-cos(x)-integral(-cos(x) dx) the new integral is easy integral (-cos(x) dx)= -sin(x) so you get your final result as integral (x* sin(x) dx)=-xcos(x)+sin(x)

### Subject: Physics

on a rigid body that is rolling without slipping for the initial and final kinetic energy should I use rotational kinetic energy ke= 1/2Iw^2 or transnational Kinetic energy ke=1/2 mv^2?

you should use a combination of the two so in your notation ke= 1/2Iw^2 + 1/2mv^2. also if you are having problems solving for a the velocity angular or transnational remember that v=w*r with r being the radius of the object. remember you can only use this relationship if it is rolling without slipping.

## Contact tutor

needs and Michael will reply soon.