Recent content by allistair

thank you for your assistence, much appreciated :)

The sample is a powder and the P, S, Si and C are present in their 'elemental form' (not sure about the english word... but I mean that they're not bonded with another element). I also have some rough amounts btw: Si: 0 < x < 1g S: 0 < x < 0.1g P: 0 < x < 0.1g Mn: 0 < x < 1g Ni: 0 < x <...

I've got a sample containing 8 substances: P, S, C and Si (+4 metals) which i need to analyse. I was planning on using aqua regia to dissolve the metals, remove the 4 substances that aren't metals (and deal with them later ^^) and then use atomic absorption spectroscopy to measure the metals'...

I'm not entirely sure what the english terms are for some of the things I'm about to say but i hope it's clear what I mean exactly. I'n my handbook the theorom is said to be: Say G is a part (which is open) of R^n, f and g are functions from G to R (f:G->R, g:G->R) and both are differentiable...

i worked it out like you said and i was able to get the answer, thanks a lot, intuitivly the answer just felt a bit wrong.

There's something in my theoretical mechanics handbook that i don't quite understand. Say you have an observer in a labratory watching 2 particles, one of which is in a state of rest (m_2) and the other one (m1) is moving towards it. the placevector of the center of mass of the system is...

you can't do A*B, you can do B*A but A*B is impossible. its pretty easy to remember 2x3*3x3 is a 2x3 (just look at the outer numbers, also the inner ones must be the same to be able to multiplicate em)

I have to write a program in maple that calculates the water rockets movement. For this i first need to model the pressure inside the water bottle and also i have to calculate how long it would take for all the water to be ejected from the water rocket, all off this numericaly because the...

i would suggest using something like TeXnicCenter

are you sure that that is the question? if they start out at the same height they should allways reach the bottem together i think...

I'm trying to find a function that gives the number of diagonals in funtion of the number of vertices but i don't see a connection both of them i looked it up and apparently there is a formula for it, for a polygon with 2n vertices the number of diagonals is 2n*(2n-3)/2, i hope i'll be able...

i'm obligated to use the pigeon hole principle, i can't use anything else (i'm not sure what you mean by 'discrete math', or did you mean that i posted this in the wrong forum?)

I got 6 problems that I needed to proove using the pigeon hole principle and I was able to solve 5 of them but this last one is giving me some problems. In each convex polygon with 2*n vertices there is at least one diagonal that isn't parallel with either one of the sides of the polygon...

yeah, that's what i meant

you're making it way to diffcult, lim(h->0) 1/h * (tan(Pi/6 + h)-1/sqrt(3)) is also lim(h->0) 1/h * (tan(Pi/6 + h)-tan(Pi/6)), lim(h->0) 1/h * f(a+h)-f(a) is the differential of f in a, so you really just need to calculate tan's differential in Pi/6