Thank you, yes you have understood me correctly! That is my question. I thought that 6!/(2!3!) was basically equivalent to finding distinct permutations of ABCDEE (which would include ABE etc but clearly not). What does 6!/(2!3!) tell you the number of?
Homework Statement
Find the number of distinct three letter words obtainable from the letters A,B,C,D,E in which E may occur 0, 1 or 2 times but the rest may occur only once.
Homework Equations
Number of combinations when picking r objects from n possibly objects in which one object is repeated...
Hello,
I am looking for a physics/engineering project that is doable over a couple of weeks and has a bit of wow factor. Building a trebuchet would be a good example but I would like to do something else. Any ideas?
Thanks.
Please could somebody explain how the coefficient of static friction can be quoted as a constant in tables etc?
\mu_s = F_s/ R
In most cases the reaction force is constant but as I push the box harder the friction force increases.
Is \mu_s actually the coefficient of limiting friction? Or...
MIT has a Physics Demo called "Rubber and Glass Rods with Tinsel and Balloon"
(Not sure if I can post links but easily found on youtube). I have watched the video several times but am a bit puzzled.
First the lab technician charges the rod by friction but then when he moves it close to the...
Hey, could I pester you again? I am still banging my head against the wall with this question. I have
\int_{0}^{2\pi} d\phi \int_{0}^{\pi} d\theta \int_{0}^{\infty} dr \, r \sin(\theta)...
Doesn't the \vec{b}.\vec{r} term then become a horrible mess though?
Like b_{1}cos\theta sin \phi +b_{2}sin\theta sin \phi+... which is a pain because it is in the exponential so at best you can get it in the denominator of a fraction when you integrate r out.
Hi,
Thanks, you are right about the pi factor. But what if the function f(x) was say x then there would not be a pole and residue calculus wouldn't make sense would it?
Hopefully people are still prowling the forums this close to christmas :)
I want to show that sin(ax)/x is a representation of a delta function in the limit a->infinty i.e
1) It equals 0 unless x=0
2) integrated from plus minus infinity it equals 1 and
3) multiplying by an arbitrary...
Hi,
I am trying to show that for two operators S and P:
(S+P)^{-1}=S^{-1}-S^{-1}P(S+P)^{-1}
I can't get anywhere and searching on google I am not even sure if it is possible
to solve the general case but the question gives no more hints.
Any help appreciated. Thanks.
J.
Hi I am looking at Quantum Computation by Neilsen and Chuang at the CHSH inequality.
Looking at the spin singlet state they make measurements of for example the observable Z1
and Z2-X1 and then find the expectation value of the product.
I am slightly confused here because
a) Z and X are...
Thanks that's what I wanted, I thought once I had seen this I would be able to figure it out, unfortunately it's just not clicking for me.
Can I check I have the right thinking...
\epsilon_{ijk}\partial_j A_k
For B1 you set i to 1. then that leaves two combinations for partial_j A_k...
Hi, does anyone know a link showing how to calculate curl with a Levi-Civita tensor. I can't figure it out but I am sure if I could see an actual example would be able to work out what is going on.
Thanks.