Recent content by blackcat

Ok, so if I solve the inequality, I get |x| < p/(1-p). Is that right?

All I can think of is to make x>0, but then I think that'll go down to taking a limit from the RHS. Are you saying I should take the LHS and RHS limits to get this out? As for the inequalities knowledge: I guess I have learned quite a bit but I have no idea how else I can approach this...

Well when I get to |\frac{x}{x+1}| and try to find something it's less than I can't get anywhere. So I can't say |\frac{x}{x+1}| <|x| because if x is negative then the denominator is <1. So I don't know how to simplify it to get a value out for delta. Could you give me a bigger hint? Thanks.

As the thread title. The question is actually: "Given p > 0, find d so that |x-0| < d implies |f(x)-1| < p and hence deduce that f(x) approaches 1 as x approaches 0." My problem is that, when x is near the point x=0, x can be positive and negative, I don't know how to get my delta value because...

One question. If you have this: |PQ|^2 = (b-a) • (c × d) then why is |PQ| not the square root of the RHS? If |PQ| = d then it's easier to see why it should be. But apparently it isn't. b, a, c and d are vectors. PQ is meant to have an arrow above it (so it's a vector too).

lol sorry about the notation. I don't know what I was thinking when I wrote it. But thanks for the post it makes perfect sense!

Ok Ithink I understand a bit more now, I was getting confused with terminology etc. But one final question. If you have a plane with equation say px + qy + rz = d where p, q and r are some numbers, why is it that the vector k(pi + qj + rk) (where k is a number and i, j, k are unit vectors in...

I don't get it, if they intersect at a point and after that point they will be traveling away so they must form a plane. Right?

If you have two vectors in space (so 3d) and they don't intersect, am I right in saying that it doesn't make sense to say they form a plane? Because there's no single plain we could be talking about. Whereas if they do intersect, they will always form a plane where those two lines are part of...

Hi I have some questions. If you're doing a MacLaurin expansion on a function say sinx or whatever, if you take an infinite number of terms in your series will it be 100% accurate? So will the MacLaurin series then be perfectly equal to the thing you're expanding? Also I don't really...

Wow that's really interesting, I wouldn't have guessed that would have worked. So no need to tame that one then! He was green similar to this http://www1.istockphoto.com/file_thumbview_approve/2691122/2/istockphoto_2691122_yellow_and_green_budgie.jpg but a bit more yellowish-green. His black...

You've probably all heard this/might not think it's funny but I laughed: Mathematician's wife: You don't love me anymore! All you care about is your work! Mathematician: That's not true of course I love you! Mathematician's wife: Then prove it! Mathematician: Well first we assume the contrary -...

Unfortunately he passed away this morning. I don't care for much sadness at the moment so it's much better celebrating his greatness. Always good natured, friendly, never bitten me (except for the first time) and always wanting to play. Completely adventurous with new toys and new places and...

God Nadal sucks. What a crap game for the French Open. Why did I bother watching it?

FEDERER must win! I'd hate it if Nadal wins, it will ruin my day. Come on Federer!