# Search results

1. ### Prove that f(n) = n * log (n) is O(n(1+sqrt(n))).

Homework Statement Prove that f(n) = n * log (n) is O(n(1+sqrt(n))). Homework Equations n/a The Attempt at a Solution I really don't know what to do else I wouldn't be here :? Some hints would be appreciated!
2. ### Vector field

Homework Statement A particle is attracted toward the origin by a force proportional to the cube of it's distance from the origin. (...) What would be this Force equal to (in xy plane)? The Attempt at a Solution So distance is Sqrt[x^2+y^2]... and from here I don't know what to...
3. ### Nonlinear ODE

Homework Statement I have to find the solution of (1) and show that it is not unique if y(0) = 0. I can prove it is not unique by using Picard's theorem but I don't know how to find the non trivial solution. Homework Equations (1) y(t)' = Sqrt(y(t)) The Attempt at a Solution I...
4. ### Complex derivatives

I have to solve an ODE with variation of coefficient technique. It's pretty easy but I have no clue what is the first and second derivative of e^ix and e^-ix.
5. ### Weighted lest square fit

Homework Statement I have a project for one of my class and I have been given a sheet to do the statistical analyst of my data. I am not convince this sheet is proper and I need someone to look over it it. I don't understand where my Delta R goes... Homework Equations \chi^2...
6. ### Number if rational iff it has periodic decimal expansion

My teacher gave us as excercices this: I'm pretty certain you have to prove it by contradiction, but I don't get how to represent to periodic decimal expension in a proof? Any hint is welcome, thanks in advance.
7. ### Courses Choice of course Phys-Math (McGill)

Hi, I'm going into the Joint Honours Program in Mathematics and Physics @ McGill next session... I'm seeking for help on what course to take... (also how to take them...using minerva???) I'm new to all that university stuff... not too shure how it works.... here is the list of class...
8. ### Effect of distance and temperature on tunnel current

Hi, I'm studying the effect of distance and temperature on tunneling current and I need to find information about it before... so if you guys can point me out links or articles... or just tell me what you guys know about it... I know the distance/current is an exponential function but I can't...
9. ### Theory of a Scanning Tunneling Microscope (STM)

Hi, for my integration class I am building a scanning tunnelling microscope (STM). I found some interesting designs and I choose the cheapest one (students are poor) witch uses a unimorph disk. Here is the STM design I plan to build: http://www.geocities.com/spm_stm/". For my class I need to...
10. ### Circuit of a Scanning Tunneling Microscope (STM)

Hi, for my integration class I am building a scanning tunnelling microscope (STM). I found some interesting designs and I choose the cheapest one (students are poor) witch uses a unimorph disk. The circuits are not that hard to build but I also need to understand them. I have some knowledge in...
11. ### Why is the constant 5?

Alrigth we had a lab were we had to find out what is the initial speed to give a particle to go through a vertical loop with no friction (like a rollercoaster) the equation we found was this : V_o=\sqrt{(c*G*r)} V_o = initial speed c = constant G = 9.8 m/s^2 r = radius of circle If you...
12. ### Schools University & Physics

Alright well I won't be applying for university till next year but I was wondering whats best to do... I was thinking to go McGill University (http://www.physics.mcgill.ca/ ) in Montreal as it is closed to me but is it better to like go in USA or in a foreign country to start off or I'm I better...
13. ### Nice forum!

Hi, well I'm new here.. and I wanted to congradulated you guys for making this awsome community... I've been sick all week & I've stumbled upon this forum... I read a lot of stuff here & learned way more then if I went to school... anyways thats about it, I should be around here now hoping to...