460 reputation
15
bio website
location Jackson, MS
age 83
visits member for 1 year, 11 months
seen 13 hours ago

Originally a philosophy major. Then psychology. Retired electrical engineer (CCNY 1958) with lifetime interest in mathematics and my difficulty with it. Some graduate engineering at NYU. Lots of circuit design in the sixties. Master's in mathematics from Jackson State University in 2009. Planning to start a blog on a radially different view of mathematics and understanding mathematics in 2013 if resolution and finances hold.


Mar
26
answered How do you define functions for non-mathematicians?
Mar
19
comment Why limits work
x/x is an interesting function. By definition, a/b means that number which when multiplied by b equals a. Every number when multiplied by 0 equals 0. So 0/0 stands for every number, i.e., in graph terms, the entire y axis. That is hardly a hole. If anything it's the one dimensional universe no matter how many people say otherwise.
Mar
18
comment Why limits work
@Dave L. Renfro: I disagree. The key idea is that the function x/x cannot be evaluated at zero by substitution. The function does not have a hole in it. It has a value that can't be found by substituting in the usual way. This is a vital difference. For that matter, its existence can't even be determined directly. This is the essential idea and I have never seen a clear description of it. It's exactly the same for all of the many explanations I've seen for why 0.99999.... = 1. It's a matter of our not being able to carry out the summation directly, though in this case we can algebraically.
Mar
18
comment Why limits work
Nick I should have mentioned that in the case of the two series that I mentioned, we don't need the notion of a limit to sum them since both are geometric so we can sum them algebraically.
Mar
17
comment Why limits work
Nick, I forgot to add that that same idea of a limit explains why such expressions as 0.999....=1 and 0.333...=1/3. The reason is that we cannot sum all of the terms of the infinite series but here too if we get increasingly and arbitrarily close to a value we can take the infinite sum to BE the value.
Mar
17
answered Why limits work
Mar
11
awarded  Commentator
Feb
19
answered Active learning vs Passive learning in Math
Feb
19
answered What's the intuition behind Pythagoras' theorem?
Jan
7
answered How can I explain my 9 years old brother that $8a\cdot4a \neq 64a$
Dec
29
asked Limitations and alternatives to Riemann Integral
Dec
2
awarded  Yearling
Nov
14
answered What does it mean to solve a math problem analytically?
Nov
11
answered Question on meaning probability of coin tosses?
Oct
28
answered Derivative in interesting way
Oct
28
answered Is the computer changing the way we teach and learn math in schools?
Oct
22
awarded  Critic
Oct
22
awarded  Supporter
Oct
11
answered How to explain Fractional and Negative Exponents
Sep
14
comment Teaching the concept of a function.
You have the usual preconception of mathematics as abstract. There is nothing abstract about wanting to relate quantities like the height at which an object is dropped and the time to hit the ground. Or the age of an egg and the porousness of its shell. Or your age and the length of your hair if you never cut it. And so on. A "function" is a way to express such a relationship. There is no "pure" and "applied" mathematics. The applications of mathematics are not about mathematics. And neither are lemma, definition, theorem, proof, and corollaries. Mathematics is about achieving, constructing.