Recent content by chemistry1

Well, I know how to add vectors but only if they're 2d...

Hi, I know what are the steps to determine if a molecule is polar or not, but I'm having one small problem. When I have determined teh geometrical shape of my molecule and drew the vectors of the polar bonds that goes from the least electronegative atom to the most electronegative atom, how...

Yes, I also noticed it. Ok, thank you!

But shouldn't we say : y --> -2^(-) and not y --> 2^(-) ?

Hi, I have a question about : http://imgur.com/RU7PvtJ I actually understand what I need to do. I need to see if both one sided limits are the same to establish that the limit exists. The only thing which I just find weird is the "since y --> 2^(-) implies y<-2" Can somebody explain me...

Nah, its okay, no need for that anymore.

I was wondering, when we consider several functions at once in the same graph, is it ok if this whole is not a function itself ? Do we care about whether this whole is function or not ?

Hi, I'm having trouble understanding the following fact about limits : If f(x)<=g(x) for all x on (a,b) (except possibly at c) and a<c<b then, lim f(x) <= lim g(x) x -> c x->c Here's how I interpret the definition : We have two functions f(x) and g(x), and the inequality f(x)<=g(x)...

I don't think I understand your explanation... Didn't Euclid "prove" with proposition 13 that the sum of two angles were equal to two right angles ? And that we begin the demonstration assuming that the sum of the angle CBA and ABD were equal to two right angles ? What role does postulate 4 play...

http://aleph0.clarku.edu/~djoyce/java/elements/bookI/propI14.html Hi, I was reading proposition 14 of Euclid's elements and there is only one thing which I find weird : why do we need postulate 4 to conclude that " the sum of the angles CBA and ABE equals the sum of the angles CBA and ABD."...

Well, I do understand your first part. Now, for the second part, are you saying that because the empty set has no elements, it can't satisfy(be a subset) of B?

Hi, I was wondering, how can a null set be a subset of other sets? Could anyone explain the idea in non technical terms, I'm just a beginner. :) Thank you!

Ok, Thank you again. I didn't know the standard way...^^

Well, we need two different sorts, so we have a total combination of 9 for 10 different flavour. For example, if we consider each flavour a number, then : (1,2) (1,3) ... til (1,10) Now, if we want to see for the second flavour, we already did the combination (1,2), so we must substract 1...

Hi, An ice cream shop sells ten different flavors of ice cream. You order a two- scoop sundae. In how many ways can you choose the flavors for the sundae if the two scoops in the sundae are different flavors? That's what I did : 9+(9-1)+(9-2)+...+(9-9)=45 Would this be any good ...