Search found 20 matches

by kbinferno
Mon Sep 10, 2012 4:02 pm UTC
Forum: Mathematics
Topic: Inexperienced proofer
Replies: 10
Views: 5512

Re: Inexperienced proofer

That's a good strategy. With set theory, another strategy that works a lot is a long one-line showing how two expressions are equivalent by symbolic manipulation of the definitions. The nice thing about that is that that all of those definitions are usually reversible so you can cover both halves o...
by kbinferno
Mon Sep 10, 2012 4:25 am UTC
Forum: Mathematics
Topic: Inexperienced proofer
Replies: 10
Views: 5512

Re: Inexperienced proofer

I'm just doing how I was taught to tackle proofs for showing two sets are equal. Show any element in set A is also an element of set B, then vice-versa.
by kbinferno
Mon Sep 10, 2012 2:29 am UTC
Forum: Mathematics
Topic: Inexperienced proofer
Replies: 10
Views: 5512

Re: Inexperienced proofer

This is what I ended up with: Assume (g o f)^-1 (H) < f^-1 (g^-1 (H)). Let x be in f^-1 (g^-1 (H)). The function (g o f)(x) takes elements x in A and tramsforms them into elements in C, by 1.1.12*. The inverse, (g o f)^-1 (H), takes elements in H<C, transforms them under the inage g^-1 ,then transfo...
by kbinferno
Sun Sep 09, 2012 11:52 pm UTC
Forum: Mathematics
Topic: Inexperienced proofer
Replies: 10
Views: 5512

Inexperienced proofer

Let f : A -> B and g : B -> C be functions and let H be a subset of C. Prove (g o f)-1 (H) = f-1 (g-1 (H)). I can try to prove they are subsets of each other or use a Not Q => Not P argument. The only lemma I have to work with is that f(g(x)) = (f o g)(x). My first attempt I started with "Let I...
by kbinferno
Thu May 12, 2011 4:47 am UTC
Forum: Mathematics
Topic: Sum of a series (test review)
Replies: 4
Views: 1041

Re: Sum of a series (test review)

Try some easier problems first: What is \sum_{n=0}^\infty nx^{n-1} ? (Hint: It's the derivative of something.) This would just be 1/(1-x)^2 right, since it would be the derivative of 1/(1-x) Okay, now what is \sum_{n=0}^\infty nx^n ? I guess when n's are coefficients it's throwing me off.. ...
by kbinferno
Thu May 12, 2011 2:41 am UTC
Forum: Mathematics
Topic: Sum of a series (test review)
Replies: 4
Views: 1041

Re: Sum of a series (test review)

We never reviewed anything about generating functions.. and the third derivative gives us the denominator is there something else I'm missing? Is the only way to approach this with g.f.?
by kbinferno
Thu May 12, 2011 1:50 am UTC
Forum: Mathematics
Topic: Sum of a series (test review)
Replies: 4
Views: 1041

Sum of a series (test review)

So this question popped up on an exam, and I couldn't get the second part. We won't be getting the exams back due to it being the end of the semester and I am pulling my hair out. For one hard problem, they give us the answer, but we have to prove that it equals the given answer. Kinda like how you ...
by kbinferno
Fri Apr 22, 2011 4:23 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0889: "Turtles"
Replies: 207
Views: 60066

Re: 0889: Turtles

in before this doesn't fit into romance sarcasm math or language
by kbinferno
Mon Apr 18, 2011 1:56 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0887: "Future Timeline"
Replies: 192
Views: 57309

Re: 0887: "Future Timeline"

what makes this creepy, is that today is my birthday and I am always stressed out about what the future is going to bring.. get out of my head randall!!
by kbinferno
Fri Apr 01, 2011 10:07 pm UTC
Forum: Coding
Topic: Noob Question: How to make an equation look simpler
Replies: 18
Views: 2914

Re: Noob Question: How to make a equation look simpler

Sorry for the miscommunication; it's actually required by my universities' coding standards to have the syntax simplified like this whenever possible. I've actually lost points on an assignment before using "n = n + 1" instead óf "n += 1". :roll:
by kbinferno
Fri Apr 01, 2011 9:53 pm UTC
Forum: Coding
Topic: Noob Question: How to make an equation look simpler
Replies: 18
Views: 2914

Noob Question: How to make an equation look simpler

Okay, I'm writing a code in Python that has to deal with the Collatz Conjecture, and I've come to the following piece: # above I have already error-checked n to be a positive integer while n != 1: if n % 2 == 0: n = n / 2 # which can be simplified into: # n /= 2 else: n = (n * 3) + 1 # but how can I...
by kbinferno
Wed Mar 30, 2011 4:14 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0879: "Lamp"
Replies: 151
Views: 36576

Re: 0879: "Lamp"

This was the first comic that made me laugh out loud in a long time.
by kbinferno
Mon Mar 07, 2011 5:01 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0869: "Server Attention Span"
Replies: 90
Views: 25737

0869: "Server Attention Span"

http://imgs.xkcd.com/comics/server_attention_span.png Alt Text: "They have to keep the adjacent rack units empty. Otherwise, half the entries in their /var/log/syslog are just 'SERVER BELOW TRYING TO START CONVERSATION *AGAIN*.' and 'WISH THEY'D STOP GIVING HIM SO MUCH COFFEE IT SPLATTERS EVER...
by kbinferno
Thu Jan 13, 2011 7:40 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0846: "Dental Nerve"
Replies: 135
Views: 36655

Re: 0846: "Dental Nerve"

http://en.wikipedia.org/wiki/Kesha 1500 on her SAT. Supposedly. I'm actually pretty sure she's retarded. I don't care if the song's a joke, you wrote it. People sing it and they think you mean it because they're retarded. Why would she do this to us?!? I believe that 1500 is the combined score she ...
by kbinferno
Wed Jan 12, 2011 9:50 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0846: "Dental Nerve"
Replies: 135
Views: 36655

Re: 0846: "Dental Nerve"

There are quite a few songs based on dental hygiene. Like this one.
by kbinferno
Wed Dec 22, 2010 5:43 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0837: "Coupon Code"
Replies: 86
Views: 28512

Re: 0837: Coupon Code

Werewolf wrote:Epic win.
If I start an online site, I am putting that as an automatic coupon code.

Really? If you do, I'll buy everything :)

Does anyone else see the coupon code box as an opportunity, and then google the website + "coupon codes" ?
by kbinferno
Tue Apr 06, 2010 6:40 pm UTC
Forum: Mathematics
Topic: Calculus Test (Antiderivatives, etc)
Replies: 12
Views: 2562

Re: Calculus Test (Antiderivatives, etc)

@achan1058 Thanks, I'll take a look at those programs. =] @Qaanol lol thanks =] I am actually looking forward to learning how to make the maths look pretty. Also, I appreciate pointing out some of the errors. Making x=u+1 was probably me just running out of time on the test, but I think I solved the...
by kbinferno
Tue Apr 06, 2010 4:28 am UTC
Forum: Mathematics
Topic: Calculus Test (Antiderivatives, etc)
Replies: 12
Views: 2562

Re: Calculus Test (Antiderivatives, etc)

For the "fancy math" you'll probably want to check out this thread http://forums.xkcd.com/viewtopic.php?f=17&t=21939 and just learn a little latex in general. If you're a math person then Latex will become quite handy for you. Also, it'd be nice if you posted your work for the problem...
by kbinferno
Tue Apr 06, 2010 4:15 am UTC
Forum: Mathematics
Topic: Calculus Test (Antiderivatives, etc)
Replies: 12
Views: 2562

Re: Calculus Test (Antiderivatives, etc)

Also, if anyone has any advice on a program that will help me out with using the math tags, that'd be pretty cool too. Being able to actually post the integral symbol, sigma, etc would be extremely helpful. =]
by kbinferno
Tue Apr 06, 2010 4:10 am UTC
Forum: Mathematics
Topic: Calculus Test (Antiderivatives, etc)
Replies: 12
Views: 2562

Calculus Test (Antiderivatives, etc)

So I got my Calculus test back from my teacher and I wanted to know why some of these problems were wrong. 50 problems, 6 wrong. Not too bad, but, eh. I re-looked over my work and for some of them I can't figure out where my mistake was. The unit is done and over with, but, I want to make sure I do ...

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