Recent content by Chantry

Not sure why, but it's not letting me edit the first post. It should be kx^(b-1) *exp(-ax^b) not ∫kx^(b-a) *exp(-ax^b), but anyway, I took another crack at it and I solved it! u = ax^b du = abx^(b-1) dx ∫kx^(b-1) *exp(-ax^b) dx = k/(ab)∫exp(-u) du = k/ab[1] = 1, so k = ab. ∫kx^(b)...

Bumping back to first page.

Homework Statement This is the full question, but we're only asked to do b. A random variable x has a Weibull Distribution if and only if its probability density is given by f(x) = {kx^(b-a) *exp(-ax^b) for x > 0 } where a and b > 0. a) Express k in terms of a and b. b) Show that u = a^(-1/b)...

Definitely missed that completely. Thanks a lot. It's amazing how the simplest things can sometimes give you so much trouble. Just to make sure I'm understanding it correctly, the U 1 to infinite of (0,n) is saying you're doing a union of {0, .. Real Values, .., 1} U {0, .., 2} U {0,..,3}...

Homework Statement I'm reading through the introductory pages of my real analysis book and for some reason I can't wrap my head around this seemingly simple concept. The book is talking about collections of sets and something new to me called the "index set". I apologize ahead of time...

To be clear, you're saying that you can't just simplify (a^i)^i to a^(i^2), BUT i^i does have infinite different values, correct? This is starting to boggle my mind a little bit. I can't seem to wrap my head around it. I'm reading the wikipedia page...

Can someone explain if this is true or if there's anything wrong with the following logic? e^ix = cos(x) + isin(x) Let x = pi/2 + 2npi Then, e^ix = i Take both sides to the exponent i, e^-x = i^i e^-(pi/2 + 2npi) = i^i But, e^(pi/2 + 2npi) has infinite different values. I've been looking...

Thanks for the help :). I now understand where they get the sin(x) + rsin(x) in the numerator, and where the 1 + r^2 comes from in the denominator. However, how do they get the 2rcos(2x) in the denominator? EDIT: Never mind, I figured it out. I forgot about cos(x) = 1/2(e^ix + e^-ix)...

Homework Statement http://www-thphys.physics.ox.ac.uk/people/JamesBinney/complex.pdf Example 1.2 (Page 6) Homework Equations De Moivre's Theorem, Euler's Formula, and other simple complex number theory formulas The Attempt at a Solution I'm having troubles understanding the format, which...

Don't forget that for some problems you can differentiate or integrate the power series of a simpler function.

All I see is an image to a chinese chat program called qq.

Not a fan of sarcasm. Particularly when I'm trying to help you out.

They're just asking which are subspaces of R^n. So you have to show: a) cV, where V is a subset of the subspace, is an element of the subspace. and b) v + w, where v,w are elements of the subspace, is again in the subspace. It also wants to know what the domain of the subspace is from what I...

It's D=fxx(fyy)-(fxfy)^2 If d > 0, and fxx > 0, it's a local minimum or fxx < 0, it's a local maximum if d < 0, then it's a saddle point. However, you can't use this for this function as it's a function in terms of one variable. So, r=(1-x)(1+x) = 1 - x^2 Which is a...

You have to prove: a) It's linearly independent: If S spans, that means ... None of the vectors in S are a linear combination of another. How can you prove this? Think .. av1 + bv2 + cv3 .. + Lvn = 0, implies a,b,c .. L = 0. b): It spans. If S spans V, that means that any vector of V...