Recent content by mikehibbert

I did it :D I won't type it all out because it would take forever, but I got both sides of the equation to equal :)

Homework Statement The particles of an ink blob dropped into a large container of water diffuse outward and obey the radial diffusion equation: dn/dt = (D/r2) (d/dr) (r2* (dn/dr) ) where n(r,t) is the density of ink particles at point r at time t and D is the diffusion constant. Verify, by...

but i still can't see how that proves it? and i needed the marks, so overkill it was :P

ok - could someone validate my answer please? i got 4 atoms in one crystal, the volume of one atom: ( pi * (2^(3/2)) * (a^3) ) / 48 the volume of the crystal is a^3 giving a packing fraction of 0.236?

I used a wronskian in the end!

Homework Statement Write down the number of nearest neighbours in a FCC structure, calculate the angle between the bonds and the packing fraction. Homework Equations Literally don't know where to start! The Attempt at a Solution Very confused at the moment. Tried to look up...

but do you think i have to find the values of the constants? surely it's impossible? because I have three unknowns - I need three equations?

i'm struggling i must admit :S this would give me: (c1)x^2 = 0 (3c2 + c3 + 2c4)x = 0 (2c2 + c3 + 5c4) =0 yes?

Homework Statement Show that the set of functions: x^2 3x+2 x-1 2x+5 are linearly dependent. Homework Equations - The Attempt at a Solution I know that you have to show that you can put constants in front of each equation (that aren't all zero) such that: c1y1 + c2y2...

i'm gunna have to. gotta be handed in at 10am tomo grrr. i give in :P the easiest question on the sheet has beaten me!

i swear I'm going to kill the person than wrote this question... now I'm getting y = 2(x^2) + x^2 + c which doesn't really look right to me :S

grrr I'm literally an idiot...

oh and i can't see where a 2y would come from?? the LHS integral is (y^2) / 2 + y which factorizes to 0.5y(y+1) ? then re-arranges to what i said earlier.

yes i did mean y = 2(x^2) / (y+1) sorry. and there should be a +c on the end, granted. but my solution is still wrong isn't it? you can't have a y on both sides?

argh I've literally been thinking about this for like two hours, it's ridiculous. integrating (y+1) wrt y gives: (y^2)/2 + y and integrating 2x wrt x gives: x^2 giving (y^2)/2 + y = x^2 and rearranged gives y = 2x / (y+1) i still get it no matter how many times i think of it :( arrgghhh