Recent content by doive

thank you guys! I had tried checking it but couldn't be certain it wasn't my dodgy arithmetic!

Homework Statement I have conflicting notes and even textbooks about where i should and shouldn't have factors of 2 when doing Fourier series. I just want to check once and for all I'm doing it right and not introducing erroneous factors of 2 or omitting anyHomework Equations \tilde{f}(x)=...

It really depends on the complexity of the problem, only recently Grigoriy Perelman solved the Poincaré conjecture which was proposed way back in 1904. So it can take a very long time indeed! In my experience, what separates the good from the bad mathematicians at university undergrad level and...

This is actually a very good way to solve it, but it's quite specific to this case/cases where you can get a bracket with (x-a)^3 = c By replacing x+1 by z you have: z3=-1 Using a roots of unity method (i think that's the name) you can see z= ei(pi+2k*pi/3) therefore x= ei(pi+2k*pi/3)-1

It looks to me like you did the factorisation right in the original post and i agree that you should get: x^3+ 3x^2 + 3x +2 = 0 Now there are a few different ways to approach this, the simplest being the factor theorem. To use the factor theorem pick some values for x and see if they satisfy...

i've tried stuff like that before and i think i must be doing it wrong :s i can input as much LaTeX as i like, but i can't get it to display anywhere? i have the majority of the document prepared in word and just want to add half a dozen formulae. How can i do that in this package? (as you can...

I'm looking for some software which will allow me to view/write/edit LaTeX equations. At the moment I am inputting my equations into this forum and clicking "preview post" in order to get equations in the LaTeX format, which is pretty unsatisfactory (though up till now has been so irregular as...

You have calculated the force due to the electric field, not the field itself. I believe the eq you are looking for is: E=\frac{Q}{4\pi\epsilon_0r^{2}}

^ assuming your conversion of kcal to joules is correct that seems like a model solution to me.

sorry CFDFEAGURU i did mean milli honest - my brain was behind my fingers! Thanks for that, it seems to be the conventional way, though i do find the solidus and brackets approach rather less clear than negative indexing. I think i may be alone in that... when you say "non-breaking" do you mean...

This is just a quick question about the convention used to write units. My assumption is that you wouldn't leave spaces between different units, but i could see this could lead to potential confusion. should i write: kms-1Mpc-1 or km s-1 Mpc-1 I guess it's normally clear from what you're...

Aaaah i get it now Since i have already worked out x from measurement i am in fact using that as the relation to z. I think my problem previously wad that i was using the value i had calculated for Ho to work out dA rather than the other way about. You're explanation was very simple but it...

Homework Statement I've been measuring hubble's constant by calcultaing the redshift on a star and it's distance from Earth using a simple method of assuming galaxies have a standard size, then measuring their apparent size to gauge their distance away. To refine the model i have been asked...

Ah i see! so instead of working out the B field for the quite complicated shape i just calculate B for the solid wire and then imagine a cylinder in the position of the drill hole with current flowing in the opposite direction. So if i have B due to solid wire all i have to find is the B due...

magnetic field within "holey" wire Homework Statement You have a wire running along the z axis with radius a, a hole is drilled in this wire, off-centre, but also in the z-direction. The centre of the hole is distance d from the centre of the wire, it has radius b. There is also uniform...