Recent content by Lucy Yeats

Hi, I've been reading about four-vectors and I have two quick questions: If the position 4-vector is timelike, are the corresponding momentum and acceleration vectors also timelike? If the position 4-vector is spacelike, are the corresponding momentum and acceleration vectors also...

Thanks for your help. To rephrase my question: H/En>=En/En> (where /x> is ket x) Multiplying by bra x, <x/H/En>=En<x/En>. I would like to know why <x/H/En>=H<x/En>.

We were told in lectures that the time independent Schrödinger equation can be applied to wavefunctions, i.e. \frac{hbar^2}{2m}\frac{d^2U}{dx^2}+V(x)U=EU where U is the wavefunction bra x ket psi. I don't understand why this is valid, as wavefunctions are probability amplitudes, and operators...

Ah, that makes sense now. Thank you very very much! :-)

How will I get rid of the components of A^T when I multiply out that expression?

So is there any way to put that formula back into vector form? I know the elements of the matrix A^TA are all dot products, but not how to get rid of the matrix.

This is 4 mark question that's meant to take 4 minutes in an exam, but there's quite a lot of algebra for that...

Thanks! So I then get a long complicated formula by solving those equations by eliminating variables in the normal way?

So I'd have a.ax+b.ay+c.az=d.a, but I can't see the next step.

Sorry, I see what you mean about the a^bc thing. Ignore the last post and I'll try again. :-)

I know that ln(z1z2)=lnz1+lnz2+2πin, where n is an integer. I don't see why I need to use logs in this question. why can't I say: (-1x-1)^(-i)=1^(-i) (-1)^(-i)x(-1)^(-i)=((-1)^(-i))^2=(-1)^(-2i)=((-1)^2)^(-i)=1^(-i) Thanks for helping!

Homework Statement Four 3-vectors a, b, c, and d are related by the equation ax + by + cz = d; where x, y, and z are real parameters. Using a suitable combination of scalar and vector products, find x, y, and z in terms of the vectors. Homework Equations The Attempt at a Solution...

Homework Statement Verify that the equation (z1z2)^w=(z1^w)(z2^w) is violated for z1=z2=-1 and w=-i. Under what conditions on the complex values z1 and z2 does the equation hold for all complex values of w? Homework Equations The Attempt at a Solution...

Also, the sum is from j=1 to n. So the ith element of the vector u is the sum of the elements of one row of the matrix U with the elements of the vector j.

I attached the paper about a minute after I posted; I think it's there now. :-)