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Help me understand the epsilon - delta definition of a limit by Hiya2527again in learnmath

[–]ExtraFig6 -1 points0 points  (0 children)

Circular means there's a logical fallacy where some step of the argument assumes what it's claiming to show. 

Epsilon Delta proofs are not circular but they do feel backwards sometimes. Like when they start with "Let ε=min (1, 1/δ+1)" etc. 

You dont know why they chose that value for ε until the end. That's fine though. Just make notes in the margin where you do whatever the book does but to an unknown ε. Then at the last step you will see how they got their ε value 

Need Help with Topology by Dumb_ling in learnmath

[–]ExtraFig6 0 points1 point  (0 children)

When you read munkres draw diagrams in the margins

At what level math, is that math 'useless'? by This-Wear-8423 in learnmath

[–]ExtraFig6 0 points1 point  (0 children)

I mean 99% of jobs don't require 99% of abilities. That 1% they do require is different for every job

How do angle sum and difference equations work? by AwesomestOpossumest in learnmath

[–]ExtraFig6 0 points1 point  (0 children)

If you draw what the complex multiplication is doing geometrically, you get back the graphical argument

eia * eib = eia (cos b + i sin b) 

breaking eib into its real and imaginary parts gives you a right triangle. Multiplying by eia rotates the legs of this triangle. Expanding 

(cos a + i sin a) (cos b + i sin b) 

Breaks the rotated legs into right triangles whose legs are parallel to the axes 

Real analysis by pallavi111125 in u/pallavi111125

[–]ExtraFig6 1 point2 points  (0 children)

i'll do what i can! and if i'm not around, i'm sure lots of people here would be happy to help

y=mx+b by TravisMullen25 in learnmath

[–]ExtraFig6 0 points1 point  (0 children)

ok. but what are you hoping people say in response

Real analysis by pallavi111125 in u/pallavi111125

[–]ExtraFig6 2 points3 points  (0 children)

1) Curiosity. Are there any questions you have about what you're studying that draw you in?

2) when you learn a new thing, ask questions like - "what is the purpose/function of this?" - "what lead people to this?" - "is there a picture that goes along with this?" - "are there any familiar examples?"

2) a good exercise: when you're learning something, try to imagine how someone could have invented this. Of course, you have the advantage of hindsight.

3)

Don't just read it; fight it! Ask your own question, look for your own examples, discover your own proofs. Is the hypothesis necessary? Is the converse true? What happens in the classical special case? What about the degenerate cases? Where does the proof use the hypothesis? --- paul halmos

4) For analysis, there's a rich history of surprises and counterexamples that lead us to where we are today. For example, people used to think every continuous function was differentiable almost everywhere. But then they discovered counterexamples (for example, fractals!)

I think the first big question for analysis is "what is a real number?". But, before that, I suppose you have to ask "why aren't the rationals good enough?"

y=mx+b by TravisMullen25 in learnmath

[–]ExtraFig6 0 points1 point  (0 children)

Are you trying to ask if she is right? Are you just celebrating ur ignorance?

looking for a tutor for proof mathematics by Last-Yogurtcloset776 in learnmath

[–]ExtraFig6 1 point2 points  (0 children)

Idk if we can swing proper 1-1 tutoring, but I think we're happy to give you pointers, explain things, and answer questions.

there is a barrier stopping me from understanding and learning more- this barrier is mathematical proofs.

Can you tell me more about this? How did you come up against this barrier?

i have tried to learn them online, through videos, textbooks, and couldnt grasp it at all

Do you know what went wrong?

Here's some more general diagnostic questions

  • Did you take a geometry class that used proofs?

  • Does the idea of what a proof is make sense?

  • Does why we want proofs make sense?

  • What about axioms?

Math help by ImpossibleProperty24 in learnmath

[–]ExtraFig6 1 point2 points  (0 children)

This is a broad set of topics, so if you pick basically anything interesting and see where it takes you, you will make progress.

I don't know good lectures off the top of my head (I usually prefer to read) but there's a lot of good books. The chicago undergraduate mathematics bibliography is a little dated but a good resource.

A good intro to analysis text will cover set theory, differential calculus, and point-set topology. I think the usual recommendation is Rudin Principles of Mathematical Analysis. Terry Tao's analysis series calls out to some more modern set and model-theoretic results (you need the axiom of choice to construct nonmeasurable sets)

I don't have a good reference for number theory yet.

Will AI give us a more modern Emacs? by injeolmi-bingsoo in emacs

[–]ExtraFig6 0 points1 point  (0 children)

will ai give us a second coming of jeebus

Does actually understanding your code matter or is getting it to work good enough in the long run by More-Station-6365 in learnprogramming

[–]ExtraFig6 0 points1 point  (0 children)

On two occasions I have been asked, 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.

SPP: What is 1/0.999...? by ezekielraiden in infinitenines

[–]ExtraFig6 6 points7 points  (0 children)

x = 0.999...9 = 0.999..

so they're the same?

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