Recent content by RandomMystery

Okay, thanks but I still don't understand the multi variable summation notation- What does the i,j,k under the sigma represent and why is there nothing on "top" of the sigma? Does this notation also assume that: "the summation is meant to be over all triples i, j, k where...

Well, we just learned that the lim x -> a notation simply means that the x value is approaching a, but it isn't a. So it is the value right next to a. I guess it's just a practical and less formal way of saying the same thing, although simply saying that x minus a is greater than zero...

"Given ϵ>0 , there exists δ1>0 " Where did ϵ and δ come from? I don't recall learning this at all when learning limits.

I can't understand the sum notation shown in Wikipedia or in this article: http://mathforum.org/library/drmath/view/53159.html I want to find the sum notation for (a+b+c)^n however I can't understand the sum notation: I don't understand the use of brackets or what they mean here and in the...

Can you find the surface area of a sphere without using the cylinder formula? (I mean, you can end up with the same formula, but you use different reasoning)

Okay, is there a better way of stating my example? Is this okay: Diminishing returns especially happen when, for example, a man chooses to major in a state college (with state scholarships) only to choose to live off his wife upon completion of the degree. Of course he may have some...

Sorry, I didn't mean to make anyone mad. It could have easily been a man who lives of his wife, I just stated the traditional scenario. "If that same woman enhances the education (and moral compass) of her children - there is an absolute value to society that should not be diminished - IMO."...

On the what to teach, shouldn't practical things such as cooking, car mechanics, and personal accounting be required for a GED? Specially since these skills don't require high levels of abstract thinking and can be learned through apprenticeship, the skills can be more easy for younger...

The above method is too tedious, here is a better way: dy/dx = Q - ay - by^3 dx/dy = \frac{1}{Q - ay - by^3} dx = \frac{dy}{Q - ay - by^3} Now integrate both sides (I don't know how to do it) but Wolf math does...

I'm not sure this is right, but it may work!: dy/dx + (a+b.y^2)y = Q dy/dx + ay+by^3 = Q dy/dx = Q - ay - by^3 y = Qx - a\int(ydx-b\int(y^3dx Now we convert dx into dy and y terms: dy/dx = Q - ay - by^3 dx = \frac{dy}{Q - ay - by^3} Bam! Here it is y = Qx -...

Thanks for the reply, it's cleared up some things and I think I get it now. Euclid's proof shows that if P + 1 is not prime, then P + 1 can not be divided by a prime number in the finite set of prime numbers since when you divide P + 1 by a factor of P, that factor will end up dividing 1...

Why can't we make a equal some function? a = -8x \frac{a}{-8}=\frac{-8x}{-8} Here the function is globally onto. I don't understand why you choose y=0 in the discriminant: Delta = 6^2-4(-8)a instead of Delta = (6 - 6y)^2 - 4(a + 8y)(-8 - ay) We can either replace a for one function...

I don't understand how this part is valid: "If q is not prime then some prime factor p divides q. This factor p is not on our list: if it were, then it would divide P (since P is the product of every number on the list); but as we know, p divides P + 1 = q. Then p would have to divide the...

I think you can still use the quadratic equation: a has to be a value that makes this expression always true (since you can't take the square root of negative numbers): http://latex.codecogs.com/gif.latex?0\leq&space;(6-6y)^2-4(a+8y)(8+ay) I'm not sure what you do next...

I thought this expression had to be negative for there not to be any zero roots in the denominator. a> -\frac{9}{8} Why isn't that ^ the answer? I don't understand what onto and f:R-->R mean. If you plug in any number less than -9/8 on any graphing calculator, you will get a continuous...