Recent content by doodlepin

Homework Statement Find a topological space which does not have a countable basis. Homework Equations Definition of basis : A collection of subsets which satisfy: (i) union of every set equals the whole set (ii) any element from an intersection of two subsets is contained in another...

Ok i understand that. Do you have any idea what they are asking for though? Because there is no area which would cover the entire yz plane. The gaussian cylinder thing makes since to me, i just don't know how it applies to finding the charge density of an infinite plane.

Flux that passes through each end of the cylinder: E is independent of surface area at end of cylinder so flux is just E*A = ax*A where A is the area of the end of the cylinder. Charge enclose by the cylinder is charge density of infinite plane multiplied by A Area of plate enclosed by...

Yes. Except for a quick blurb in parenthesis saying: (This is a more subtle problem than it looks, and worthy of careful thought)

Homework Statement Suppose an electric field E(x,y,z) has the form: E_x = ax, E_y = 0, E_z = 0 where a is a constant. What is the charge density? How do you account for the fact that the field points in a particular direction, when the charge density is uniform? Homework Equations...

wow you are totally right. Thank you so much. Sometimes you start thinking too hard about something and you start to over analyze it. :)

Question is: X is a set and tau is a collection of subsets O of X such that X - O is either finite or all of X. Show this is a topology and completely described when a point x in X is a limit of a subset A in X. I already proved that this satisfies the conditions for defining a topology...