Math help

[Bluemofia]

Ok, I need to find the fallacy in the argument that 0=1. (int means integral)

int(dx/x)

dv = dx --> v = x
u = 1/x --> du = (-1/(x^2))dx

int(dx/x) = (1/x)(x) - int((-1/(x^2)(x)dx)

int(dx/x) = 1 + int(dx/x)

0=1

What is wrong with this proof?

 

[Perfection]

You forgot +C

 

[Bluemofia]

Wait, where would the +C go in?

 

[Integral]

Anytime you take an indefinite integral, you must add a constant of integration.

Integral

 

[Bluemofia]

At the end of the equation, correct?

int(dx/x) = (1/x)(x) - int((-1/(x^2)(x)dx) + C

 

[Hitro]

Anytime you take an indefinite integral, you must add a constant of integration.

Integral

Fricken weird.

 

[ParadigmShifter]

I suppose his username comes from liking integration i suppose (which makes him very weird).

 

[Perfection]

At the end of the equation, correct?

int(dx/x) = (1/x)(x) - int((-1/(x^2)(x)dx) + C

You could actually hold off doing it until the very last step.

I suppose his username comes from liking integration i suppose (which makes him very weird).

Nah, it comes from him wanting to brag about being in a calc class in high school. (The avatar until I corrected him used to have the bounds of integration from 0 to x, neglecting the need for a dummy variable)

 

[ParadigmShifter]

I noticed that too! But I wasn't nerdy enough to bring it up

 

[Bluemofia]

You could actually hold off doing it until the very last step.

Ah, that's why my textbook doesn't offer a good explanation of it.

Thanks!

 

[Integral]

Nah, it comes from him wanting to brag about being in a calc class in high school.

Oh, hush you.

 

[ParadigmShifter]

Differentiation > Integration (except in the Complex field maybe)

 

[ainwood]

I'm a bit rusty, but I think that the fallacy is that includes -1/x², where x = 0. Ie - the proof relies on being able to divide by zero.

 

[Godwynn]

I'm in a college calculus course and have no idea what you people are talking about. Although Integral's first post sounds a lot like the Chain Rule.

 

[Tabasco Sauce]

I'm in a college calculus course and have no idea what you people are talking about. Although Integral's first post sounds a lot like the Chain Rule.

What is this calculus that you speak of?

 

[Nobody]

Did you guys learn this stuff at school? If so what level? I did maths all the way through school and then 7th form stats, and i know i didnt do calculas, stats is normally thought to be only a little bit easyier than calculas. And i never saw any of this stuff!

 

[shortguy]

I'm in a college calculus course and have no idea what you people are talking about. Although Integral's first post sounds a lot like the Chain Rule.

No; the chain rule deals with differentiation, not integration.

 

[ainwood]

Did you guys learn this stuff at school? If so what level? I did maths all the way through school and then 7th form stats, and i know i didnt do calculas, stats is normally thought to be only a little bit easyier than calculas. And i never saw any of this stuff!

Probably because he doesn't have an equation editor to show it properly.

Instead of "int", consider it to be a "∫".

 

[Perfection]

I'm a bit rusty, but I think that the fallacy is that includes -1/x², where x = 0. Ie - the proof relies on being able to divide by zero.

Nope, you can have indefinite integrals with these kinds of holes in them.

I'm in a college calculus course and have no idea what you people are talking about. Although Integral's first post sounds a lot like the Chain Rule.

You probably haven't gotten to integration yet, which is the harder half of calculus IMO.

Did you guys learn this stuff at school? If so what level? I did maths all the way through school and then 7th form stats, and i know i didnt do calculas, stats is normally thought to be only a little bit easyier than calculas. And i never saw any of this stuff!

Yeah, it's basic calculus, something you'd see in second quarter calc or second half of first semester calc.

 

[Joe Harker]

Thank god i don't do maths any more :