Recent content by Pearce_09

Hello, Im just wondering is there a simply calculated formula for the expected value and variance for the hypergeometric distribution. I know how to do it with long calculations. I know the expected value for the binomial is = np and the variance is = npq = np(1-p) .. Is there something like...

I just don't understand how to find this other equation

im missing an equation then, which I am having trouble finding...

I use my cost equation to solve for h and got h = -5wl / 2w + 2l and when i sub that into volume and partial derive but it doesn't make any sense.. I get l = w and then that implies that h = -10/8 ... not possible to have a negative number

i know how to use lagrange.. but i was told not to for this question

ok, i have an aquarium of volume V... where the cost of the base is 5 times of the sides... let h- height , w- width, l - lenght... therefore 2hw + 2hl is the cost of the sides and 5wl is the cost of the base therefore total cost = 2hw + 2hl + 5wl --> min and i want find the dimensions to...

hello, im only having one problem with this question..and that is finding my second formula. I have an aquarium with givin volume, where the base is made of slate and the sides are made of glass..and the cost of slate is 5 times the cost of glass (per unit area) find the dimension of the...

hmmmm.. I am not sure what carries over to f(Z), but i do know that if Q did not include 0 and if it was under multiplication not addition then it would be commutative/abelian.

ok sorry, this is not wourth it.. I am wrong i the first place i screwed up.. i meant two groups.. one map Z-->Q.. but clearly I was wrong from the beginning

oh yes your right for finite sets..! .darn... well back to the drawing board

there is no function... it is just the two maps the question is Are the additive groups Z and Q isomorphic. thats it.. maybe one can say that y is mapped to y'/m

im am trying to show that Z is isomorphic to Q basically its bijective and its a homomorphism

and i have no idea what cantors diagnal arguments are..

really, they have the same cardinality... cause if they do then it is clearly surjective..because and injective map that has the same card is sujective

Hello, (**under addition** not multiplication) in my question I am trying to prove that "the set of all integers (Z)" mapped to "the set of all rational numbers (Q)" is isomorphic ie. Z --> Q through out my work I have shown that yes it is injective, and it is a homomorphism, but I have...