Question

quick question: there is no meaning in the concept of approaching infinity from the right, correct?
\(x\to\infty^+\)

Answer 1

or \(x\to-\infty^-\) wither, right?

Answer 2

either*

Answer 3

When the variable is x, and it takes on only positive values, then it becomes positively infinite. We write
\[x\to\infty^+\]

Answer 4

you gotta start really really far out i guess

Answer 5

http://www.themathpage.com/acalc/infinity.htm

Answer 6

@mathslover no, I think you are thinking of \(x\to+\infty\)

Answer 7

oh ... yes .

Answer 8

I'm still trying to figure out this:

\[\int\limits \frac{x \dot\ \sin x}{1 + \cos^2x} dx\]

Answer 9

I mean, infinity is not a number even
how do you approach a non-number from a higher number
no number can be higher than a non-number
seems like asking if 7>purple

Answer 10

@Hero it has been solved, and I will be happy to give you hints should you desire
let me note that that integral is unsolvalble (at least by me) as an indefinite integral, you must put the bounds

Answer 11

\(∞^\pm\) aren't even in the Extended real number line

Answer 12

good point^

Answer 13

I want to solve it without the bounds. I already saw the solution with bounds. Since the function is continuous I will assume an indefinite integral exists.

Answer 14

Good luck with that!
I don't know how to solve it without making use of the interval 0 to pi that it is supposed to be

Answer 15

Apparently no one or no thing does. Not even mathematica, geogebra, maple or TI. But not to worry, I know one person who for sure will be able to tell if it is possible. If it is integrable this guy will know. I kinda miss @JamesJ

Answer 16

me too :)
@zarkon actually taught me how to solve this, but he made use of the bounds heavily

Answer 17

I contacted TI about this today and they wanted me to provide them with the solution to this so that they could use it to update their algorithm.

Answer 18

wow, far out
I remember one thinbg was that we proved that\[\int_0^\infty{x\sin x\over1+\cos^2x}dx\]does not have a finite value, though I forget how we proved it.
that suggests to me that no closed form of the indefinite integral exists, but I could be wrong

Answer 19

Hmmm interesting. It may not have a finite value, but that doesn't mean it can't be solved. Last time I checked, if you take the integral of something and get sin(x) as the result....well sin(x) isn't "finite" either, but it still exists as a solution

Answer 20

There are many indefinite integrals with solutions that are not finite.

Answer 21

true... I am stretching my capacities here admittedly

Answer 22

Well, if by finite you mean a specific value.