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| Official Homework Help Thread http://www.starsonata.com/forum/viewtopic.php?f=4&t=41381 |
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| Author: | Klestiko [ Tue Nov 02, 2010 2:27 pm ] |
| Post subject: | Official Homework Help Thread |
This is here for people to ask questions regarding their homework, and the more educated members of the community to answer. Quote: Basic Guidelines: After your question is answered, edit the original post to say at the top of it in green writing, "Answered." The topic should be stated at the top of the question. Chemistry, Physics, Advanced Mathematics, English etc. When answering a question, it is up to you to decide if you want to just give the answer, or explain how to solve the problem. A preference should be stated by the person who asks the question, too. This is for any homework that can be sufficiently explained / answered over the internet. That is all. |
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| Author: | SimonV2 [ Tue Nov 02, 2010 2:29 pm ] |
| Post subject: | Re: Official Homework Help Thread |
here's an answer to just about any math problem, and half of science while yer at it. http://www.wolframalpha.com/ |
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| Author: | BlackDragon [ Tue Nov 02, 2010 5:34 pm ] |
| Post subject: | Re: Official Homework Help Thread |
Anyone here taken a Mathematical Analysis class? Either Intro or Complex? Some of the shit blows my mind. ie: 6. (5 pts) Give an example of a function f : R → R that is bounded and continuous on all of R but does not attain its maximum or its minimum anywhere on R. ~BD Edit: Answered f(x) = Arctan(x) |
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| Author: | anilv [ Tue Nov 02, 2010 6:01 pm ] |
| Post subject: | Re: Official Homework Help Thread |
BlackDragon wrote: Anyone here taken a Mathematical Analysis class? Either Intro or Complex? Some of the shit blows my mind. ie: 6. (5 pts) Give an example of a function f : R → R that is bounded and continuous on all of R but does not attain its maximum or its minimum anywhere on R. ~BD f(x) = arctan(x) Basically anything that approaches its maximum and minimum values as x goes to ± infinity. |
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| Author: | SimonV2 [ Tue Nov 02, 2010 6:10 pm ] |
| Post subject: | Re: Official Homework Help Thread |
anilv wrote: BlackDragon wrote: Anyone here taken a Mathematical Analysis class? Either Intro or Complex? Some of the shit blows my mind. ie: 6. (5 pts) Give an example of a function f : R → R that is bounded and continuous on all of R but does not attain its maximum or its minimum anywhere on R. ~BD f(x) = arctan(x) Basically anything that approaches its maximum and minimum values as x goes to ± infinity. what would it mean if it isnt bounded? |
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| Author: | anilv [ Tue Nov 02, 2010 6:23 pm ] |
| Post subject: | Re: Official Homework Help Thread |
Not sure what you mean. If you remove the boundedness condition, the question is even easier. For example, f(x) = x is a continuous function on R that does not attain its maximum or minimum values. More generally, it's always possible to find a function of this kind if its domain is not a closed and bounded subset of R. Such subsets are called compact and have many nice properties. R itself is not a bounded subset (although it is trivially closed), which is why functions of this kind exist. On the other hand, every continuous function f: [0,1] → R achieves its maximum and minimum values, where [0,1] denotes the closed interval. |
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| Author: | SimonV2 [ Tue Nov 02, 2010 6:27 pm ] |
| Post subject: | Re: Official Homework Help Thread |
ah ok, i see. |
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| Author: | bageese [ Tue Nov 02, 2010 8:15 pm ] |
| Post subject: | Re: Official Homework Help Thread |
I was making that way more complicated than it needed to be... Go me. I wasn't even relating bounded to restricted. Oops. Yeah, I want to be a teacher someday and I'm thinking it is probably going to be math. I'm currently a math major and if I can swing it a comp sci major too. I was an English/Journalism major for most of my first 2 years in college, so most of my background is in English/media studies so far. I'd be more than willing to help people out with homework! 
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| Author: | Threaten [ Wed Nov 03, 2010 12:25 am ] |
| Post subject: | Re: Official Homework Help Thread |
sin(x/2) = cos(x/2) |
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| Author: | SimonV2 [ Wed Nov 03, 2010 12:43 am ] |
| Post subject: | Re: Official Homework Help Thread |
Threaten wrote: sin(x/2) = cos(x/2) x = 4 (pi n-tan^(-1)(1-sqrt(2))), n element Z x = 4 (pi n-tan^(-1)(1+sqrt(2))), n element Z http://www.wolframalpha.com/input/?i=si ... 28x%2F2%29 |
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| Author: | Happy_Tree_Friend [ Wed Nov 03, 2010 1:02 am ] |
| Post subject: | Re: Official Homework Help Thread |
Hmm looks like more pure mathematics than what I do in the more engineering related maths....Interesting thread though, keen to see what pops up 
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| Author: | VatFF [ Wed Nov 03, 2010 1:20 am ] |
| Post subject: | Re: Official Homework Help Thread |
The equation bx^2+2bx=8 has one sollution, find b. i might be stupid, but i need help 
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| Author: | SimonV2 [ Wed Nov 03, 2010 1:30 am ] |
| Post subject: | Re: Official Homework Help Thread |
VatFF wrote: The equation bx^2+2bx=8 has one sollution, find b. i might be stupid, but i need help well... if it has one solution that means that the + and - versions of the quadratic formula equal each other.... so use that, plug it in for x, and solve for b. |
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| Author: | VatFF [ Wed Nov 03, 2010 1:31 am ] |
| Post subject: | Re: Official Homework Help Thread |
which means that inside the root of the abc formula you will get 0, right?
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| Author: | SimonV2 [ Wed Nov 03, 2010 1:34 am ] |
| Post subject: | Re: Official Homework Help Thread |
VatFF wrote: which means that inside the root of the abc formula you will get 0, right? yesh |
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