Those with no math ability - stay out

[oboeguy]

Originally posted by: Gibson486
I have actually seen profs argue over 1=.99999....math profs say yes, engineering profs say no...go figure.

That's funny, because I'd think it would be the other way around. Maybe the math prof is one of those weird dudes who's into "infinitesimals", and you'd think the engineer would say "close enough for practical purposes". For most of my purposes, 1 - 1e-8 == 1, after all.

 

[Kyteland]

Originally posted by: DrPizza
Maybe I should start a thread for the rest of you... 2 + 2 = 5 for large values of 2
(true statement, not a joke actually)

And small values of 5.

You can't forget that part.

 

[Howard]

Originally posted by: Kyteland

Originally posted by: DrPizza
Maybe I should start a thread for the rest of you... 2 + 2 = 5 for large values of 2
(true statement, not a joke actually)

And small values of 5.

You can't forget that part.

You guys have to be kidding?

 

[ILikeStuff]

Originally posted by: DrPizza
I figured since some of the people in here actually do attend college and have taken calculus, they might appreciate the non-intuitive nature of this problem. The rest of you high school kiddies, well, you just keep enjoying your christmas break.

I did attend college and took up to and including calc 3... I hate advanced math and your non-intuitive problem

 

[DrPizza]

Originally posted by: Kyteland

Originally posted by: DrPizza
Maybe I should start a thread for the rest of you... 2 + 2 = 5 for large values of 2
(true statement, not a joke actually)

And small values of 5.

You can't forget that part.

My wife actually got me that t-shirt to wear on dress-down fridays at school
as well as a Pi shirt,
and a shirt with Shrodinger's cat is dead on the front and Shrodinger's cat is alive on the back.

 

[GroundZero]

hehehehehehehehehehehehe

math can be soooooo fun! can't it?


thanks for the laugh

 

[Kyteland]

Originally posted by: Howard

Originally posted by: Kyteland

Originally posted by: DrPizza
Maybe I should start a thread for the rest of you... 2 + 2 = 5 for large values of 2
(true statement, not a joke actually)

And small values of 5.

You can't forget that part.

You guys have to be kidding?

I would never kid about a math joke.

 

[maziwanka]

Originally posted by: DrPizza

Originally posted by: mitch2891
I don't get wat you want to discuss as it is rather obvious.

If you take the sqrt of 0 the answer will be 0 and not matter how many times you nest that it will always be 0.

The sqrt of a number between 0 and 1 is always larger than the number you are taking the square root of as two numbers between 0 and 1 give a smaller number when multiplied together. does not matter what you take x to be if you nest it deep enough the answer will always be 0.999...

What is so odd about this? It is just common sense.

Well, I see you joined in June....
You missed thead that lasted for 2 years about .999... = 1 (exactly)
there were people who still couldn't fathom 1/3 + 1/3 + 1/3 = 1...
So, .333... + .333... +.333... = .999... = 1.
(not a proof, but should be a good enough demonstration)

oooooooohhhhhhhhh. i didn't picture it like this. this should be convincing for the nonbelievers

 

[maziwanka]

Originally posted by: eLiu
Rewrite the value as a sequence. This isn't analysis so I won't be specific...

s0 = sqrt(x)
s1 = sqrt(x+sqrt(x))
.
.
.
sn = sqrt(x+sqrt(sn-1)

where sn-1 is the index before sn...yeah sorry I can't come up with a clearer way of expressing that.

Sequence is monotonic (for large enough n in some situations) & bounded (easy to prove) so it converges.

So take the last equation, and replace sn and sn-1 by S (the limit).

So S = sqrt(x + sqrt(S)). We can do this because we know that sequence converges.

Apply quadratic formula.

Get: S = [1±sqrt(1 + 4*x)]/2

Can throw out the minus case. Then take limit as x->0; existence of this limit is easy to prove too...anyway, clearly S->1.

Rigor is lacking here...but you get the point.

-Eric

i like this