Showing posts with label limit. Show all posts
Showing posts with label limit. Show all posts

Thursday, August 16, 2012

That famous Cauchy definition of the limit, and another view that explains the elusive concept.

You can download all the important posts as  PDF book "Unlocking the Secrets of Quantitative Thinking".

If you can come arbitrarily close to a value, in the limit process, then that value is the limit. Of course, there has been always a question "but there is still that small error there, no matter how many elements we add, and no matter how close we are". It is true if you do not let n -> infinity. If n-> infinity then error goes to zero. But there is another nice thing about it. The "arbitrary close" statement guarantees that WHEN n -> to infinity that value will be the limit. It does not say it is the limit if you have finite number of values, no matter how big that number is. It says that, essentially, the fact that you can come "arbitrarily close", i.e. "close as much as you want" to that value, in that, and only in that case, it guarantees that, when n-> infinity, that value is the limit. No other statement will guarantee that. No other statement will guarantee that anything similar will happen when n-> infinity. That's the statement you want.

[ applied math, definition of limit, limit in mathematics, concept of a limit, limit, limiting value, integral, differential, ]

Tuesday, January 11, 2011

Some Thoughts How a Number In Math Can Be Obtained

You can download all the important posts as  PDF book "Unlocking the Secrets of Quantitative Thinking".

A number, in math, can come from measuring, counting, observing, watching, listening, dreaming, intuition, guess, random selection, ...

Limit, in math, and hence derivative and integral, are defined by incorporating a "PICK" operation in the sequence of required operations.

Pick a wrong number, and no matter how accurate your addition, subtraction, multiplication, or division is, result may be useless.

Before you add subtract, multiply, or divide, you have to pick a number. PICKING a number is very important mathematics operation.

In addition to +, -, * and /, there is one more important operation in math: PICK a number! That is how limit in calculus is defined!