FRIHOST FORUMS SEARCH FAQ TOS BLOGS COMPETITIONS
You are invited to Log in or Register a free Frihost Account!


Can anyone explain delta-epsilon method?





ptpmonitor
Our calculus teacher recently started doing limit maths using delta-epsilon method. But this method seems really complex to me and I think this method has some problem. i think sometimes we agree with un-logical decisions in order to find out the result.

The method start with this,

|f(x)-L|<epsilon if 0<|x-a|<delta,

finally we bring,

|x-a|<epsilon/k if 0<|x-a|<delta,

and tell:

so, delta=epsilon/k

Can we tell delta=epsilon/k? Specially when it is un-equality? My madam gave some answer but that was not logical also. She told in order to find out result, we need to agree with it.

Can anyone explain this method?
guissmo
disclaimer: I just came from a Calculus course this semester. If ever I'm making a mistake, please correct me.

I'll assume you've been shown a graphical representation of this and understand what the variables f(x), L, a, x, etc mean.

Since it's an if-then statement, we need to prove that a limit L exists for f(x). To do so, we must find the case wherein the "if" part is satisfied. Why? Because if the "if" part is satisfied, then the "then" part is already true too. And so, we need to find a value for delta that satisfies the "if" part.

In what you wrote,
Quote:
finally we bring,

|x-a|<epsilon/k if 0<|x-a|<delta,

You've made a series of manipulations to get to that statement.
Since epsilon/k is always greater than |x-a|<delta, then it is a good value for delta.

Therefore, delta=epsilon/k
Related topics
Free Domain & Redirect Services
can anyone explain me what happens?
multiboot DVD
Oq ta no seu Ctrl+V agora ?
xml and rss
Help Installing MySQL on SuSE Linux using ssh
C++ pointers
sql schema primary/foreign key question
MESSAGE BOARD??
Music styles - i'm confounded
Randomness is an illusion. [philosophy/science]
The BOWEN method for healing
Can anyone explain why I have this error?
What is truth and reality?
Reply to topic    Frihost Forum Index -> Science -> Education

FRIHOST HOME | FAQ | TOS | ABOUT US | CONTACT US | SITE MAP
© 2005-2011 Frihost, forums powered by phpBB.