Recent content by TobyDarkeness

Hi I'm debating a creationist and he makes the claim that no DNA can be added to a genome. Says there are no experiments. Can someone help me with concepts or sources to experiments? Thanks

Homework Statement Consider a layer of unsaturated air on Earth, 2000 m thick, whose base is at a height of 4000 m above sea level. The layer sinks and is compressed till its base is at 350 m and its top is at 1650 m. If the layer now provides a subsidence inversion, calculate the maximum...

Of course! Thanks again.

Ah i am familiar with Dirac notation but we haven't come across it yet on the course so i am uncertain how to implement it fully. Most of the resources i have come across use Dirac notation for perturbation problems. However after a bit of fiddling i have this: Adding a small perturbation...

thanks, i think i can make a start now. sorry you were right i should have made it clear. I know almost nothing about perturbation theory as in it wasn't covered so i wasn't sure where to start.

sorry, 1a) and B refer to a homework question, derive the results it asks for. Thanks for the link, ill check that out.

1. (a) If ^H_1 is a small perturbation to the Hamiltonian ˆH0, show that the first order correction to the ground state (gs) energy is: ∆E = ∫ψ*_0(x)ˆH1 ψ_0(x) dx between negative and positive infinity. where ψ0(x) is the gs wavefunction of the unperturbed system. B) (b) Take...

my attempt so far ∂T/∂t= 1/2*(∂^2T/∂x^2) T(x,t)=X(x)T(t) ∂/∂t*[X(x)T(t)]=1/2*[(∂^2)/(∂x^2)]*(X(x)T(t)) X(x)*[∂T(t)/∂t]=1/2*T(t)*[∂^2X(x)]/[∂x^2] dividing through by 1/[X(x)T(t)] 1/[T(t)]*[∂T(t)/∂t]=1/2*[1/X(x)]*(∂^2 X(x))/∂x^2 2/T(t)*∂T(t)/∂t=1/X(x)*[(∂^2X(x))/(∂x^2)]...

ok i think i have to make the constants complex but I'm not sure what I should sub in.

thanks again for the help, they worked out pretty well. just another quick question if you can help. [6] A semi-infinite bar 0 < x < ∞ is subject to periodic heating at x = 0 ; the temperature at x = 0 is T0 cosωt and is zero at x = ∞. By solving the heat equation ∂T/∂t= 1/2(∂2T/∂x2) ...

thanks allot they worked out fine, just another quick question if could help. A semi-infinite bar 0<x<infinity is subject to periodic heating at x=0; the temperature at x=0 is T_0cos\omegat and is zero at x=infinity. By solving the heat equation show that T(x,t)=...

Oh no, I was just checking I was heading in the correct direction thanks for the help haven't quite finished but it's coming together. A further question, Show that the Fourier series for the square wave defined as f(x)=-1 for -L<=x<=0 f(x)= 1 for 0<=x<=L is given by the following...

ah i see so i should use, 1/2{cos[(n*pi*x)-(m*pi*x)]+cos[(m*pi*x)+(n*pi*x)]} substitute that into my integral and proceed with the integration and Fourier series?

Homework Statement Show that the orthogonality relation for the "cosine basis functions" used in the Fourier series is 1/L\intcos[(n*pi*x)/L)]cos[(m*pi*x)/L)]dx = {Sin([n-m]*pi)}/[(n-m)*pi] + {Sin([n+m]*pi)}/[(n+m)*pi] By considering the different integer n and m, show that the right...

should there be a integral on the bottom as well? \intdm? by xcm do you mean the limits of integration for the x position or should i be able to intuitively understand where the x position should be? at a guess i would say the origin on the axis, and therefore do i need to only calculate the y...