Recent content by Freye

Oic, so essentially I'm going to be drawing a circle with an inner radius of 1 and an outer radius of 2? If so, this question was much easier than I thought. Thanks a lot for your help.

Homework Statement Let f:R^2 to R^2 be defined by f(r,theta) = (rcos(theta), rsin(theta)) Sketch the image under f of the set S = (1,2) X (0,pi) (The open brackets should be closed brackets but I am on a foreign keyboard and can't figure out how to get closed brackets). Homework...

Ok thank you, it really helps me out on a problem I am working on.

Hey guys, Continuity is generally expressed as lim x->a f(x)=f(a). But is it also correct to express it as: lim h->0 f(x+h) - f(x) = 0? Because that would imply that all numbers around f(x) would have to be very close to f(x), and that is basically what continuity is, no?

Hey, has anyone done Question 24 from Chapter 5? If so, can you help me out on getting started? I'm trying to prove it using the delta-epsilon definition of limits but I'm not really sure what epsilon to choose.

Homework Statement Suppose that A_n is, for each natural number n, some finite set of numbers in [0,1] and that A_n and A_m have no members in common if m=/n. Define f as follows: f(x) = 1/n if x is in A_n f(x) = 0 if x is not in A_n for any n Prove that the limit of f(x) as x goes to a is...

Don't worry about it Dick, I'll discuss the problem with some of my buddies tomorrow, I'm sure we'll be able to work it out together. Thanks for trying to help

If I've shown that S+v1 and S+v2 are either nonintersecting or the same (which you helped me do in the previous post), then how does it follow that V can be split into disjoint sets? All I sget from this is that S+v=S, or else S=v is not a subspace.

Hmm... No, I can't say that I do.

s2 + u can't equal s1 because s2 + some other element in S already equals s1, so that would imply u is in S, but u isn't in S. I don't think that's right...

No, I don't know how I could do that :(

We haven't learned it, so I'm assuming that the prof doesn't expect us to solve the question using it.

Homework Statement Let V = (F2)^3, the set of triples (x; y ; z) of numbers in F2, the fi eld with two elements. V is a vector space over F2. Prove that any subspace of V must have either 1, 2, 4, or 8 elements. Homework Equations F2 = {0,1} The Attempt at a Solution The only...

Ok thank you, actually that "let a and b be elemnts of U1\U2" was actually quite helpful

A subspace must be closed under addition and multiplication, use the same addition and scalar multiplication as it's parent vector space, and have the same additive identity as it's parent vector space. But how can I pick arbitrary elements of the intersection if I don't even know what V is. It...