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VBBR
Moderator
Brazil
617 Posts |
 Posted - Apr 04 2004 : 8:53:47 PM
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VBBR, you're really good with English, so I assumed that it was your native language.
Thanks for that.  In fact you are the first one to say that.
(Maybe everyone thinks that way???)
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I even assumed that you were either Canadian or from the U.S., so sorry if that offends you!
Well... If you didn't know then it's alright. I've actually learned english by surfing the web.
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Find X, (5X-3)(x+4)=34
(5x-3)(x+4)=34
5x^2 + 20x - 3x - 12 = 34
5x^2 + 17x + 24 = 0
(a little later on...)
I think it can't be solved (with what I know).
It has fallen inyo a negative square root which is not a real number.
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Calculate f ' ' if f(x) = sin(x) + ln(x) + x^-3
Is it right? Well I think I can understand everyting after the '='. (Sin, ln and x^-3). I also know what f(x) means but the "f ' ' if" part kinda confused me. Is it something like "f( )" ? Assuming inside the parenthesis there is a space.
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compute x,y values for an equation of the form dy/dx + p(x)y = q(x)
Nope. Don't quite understand that.
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Eric Coleman
Gladiator
USA
811 Posts |
Posted - Apr 04 2004 : 9:20:05 PM
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| The first problem was some simle algebra, and that's better than most people. The second question was to find the second derivative of a function, which is in the branch of mathematics called Calculus. The answer, by the way is f ' '(x) = -sin(x) - X^-2 + 4/5 * X^-5 for all X <> 0. The last equation is the standard form for a "first-order linear differential equation." The question stated doesn't have an "answer", but if you know what a "first-order linear differential equation is", then you would understand the problem is to solve an equation, then to generate a graph or field of of different values. You would use things like this in fluid dymanics simulations. Differential Equations are generally taught at a university. |
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Spodi
Warrior
USA
142 Posts |
Posted - Apr 04 2004 : 9:47:56 PM
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(5X-3)(X+4)=34
5X(X)(4) - 3(X)(4)=34
5X^2+20-3X+12=34
5X^2-3X=34-20-12
5X^2-3X=2
...
X=X
I've never delt with square roots much. Stupid Algebra I. No freaking idea about the other two also. |
vbGORE |
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Peter
Administrator
Canada
67 Posts |
Posted - Apr 04 2004 : 11:15:37 PM
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I can solve those Eric, do I get bonus points? :D
Ugh, that reminds me of the calc exam I have to write in about 2 weeks. Its all about differential equations (up to 2nd order homogeneous), taylor and maclaurin series, and functions of 2 or more variables. That and vector calculus :(
What grade are you guys in? In Canada you would learn the answer to the first question around grade 11, the answer to the 2nd one in grade 12 and the answer to the third in first year university.
Are people interested in just general math tutorials? It might help a bit in programming, but then again you might as well go to the library and pick up a book about it rather than reading an online tutorial. Although sometimes it is helpful to have a non-mathematician explain math, since mathmaticians are crazy (I'm not in math, but the crazy part is still up to the jury) ;)
PS: Spodi, I think something is a little wonky with your solution there ;)
(5X-3)(X+4)=34 expands to 5X*X + 20X - 3X - 12 = 34. You have to multiply the first term in the first bracket (5X) by all of the terms in the 2nd bracket in succession, then move on to the 2nd term etc.
If you want to find the roots of that equation you have to sub it into the quadratic formula. If you have an equation in the form aX^2 + bX + c = 0 then:
x= [-b +/- sqr(b^2 - 4ac)] / 2a
If you have a negative inside the square root that means no real roots exist, but there are complex roots. You can use the fact that i^2 = -1 to get rid of the negative, do the square root, and get a pair of complex conjugates. But I wouldnt worry too much about that, it isnt useful very often in games (but then again it sometimes is).
Oh yeah, and Eric does have other moderators on the site to help him out with approving news. I'm one of the admins and almar, brykovian, and rag on a stick are the other mods. I usually try to check the page at least once a day, but usually 3-4 times for any new postings.
Peter |
Talos Studios - VoodooVB - VB Gamer
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VBBR
Moderator
Brazil
617 Posts |
Posted - Apr 05 2004 : 10:55:25 AM
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Hum... if that's something in university level then I definetly don't know it... I don't know how my grade is called in USA or Canada, so sorry about that. But I know everything up to matrices (if the order is the same, which probably isn't).
But if some very complex math is required, then Eric or Peter, the Mathematicians (seeing your post, Peter, I kind of got scared by math... or you =D) well they can help me (us) in the complicated parts. But I think the major is related to VB, DirectX, OpenGL etc.
Oh and I don't know how to solve negative square roots.
Yet. =D |
Whatever. Who knows... |
Edited by - VBBR on Apr 05 2004 12:55:42 PM |
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Peter
Administrator
Canada
67 Posts |
Posted - Apr 05 2004 : 3:55:30 PM
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Oh, I'm not really that good at math. I can take it and learn it, but I'm not anywhere close to brilliant at it. Kind of discouraging when some people in your class get 100s on all the tests and you get 70s lol. Then again I am a slacker =)
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Talos Studios - VoodooVB - VB Gamer
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VBBR
Moderator
Brazil
617 Posts |
Posted - Apr 05 2004 : 4:02:38 PM
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Well I guess then that you've just learned more than I...
I was thinking... maybe a tutorial on simple collision detection would be a good idea? |
Whatever. Who knows... |
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Peter
Administrator
Canada
67 Posts |
Posted - Apr 05 2004 : 6:41:10 PM
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Yeah, I have a lot of such tutorials at VoodooVB though, including ones one collision detection between rectangles, circles, and polygons, which even include utilities to even easily draw the collision areas. Check my signature for the link.
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Talos Studios - VoodooVB - VB Gamer
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VBBR
Moderator
Brazil
617 Posts |
Posted - Apr 05 2004 : 6:56:27 PM
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Hum... finally this signature of yours will be useful for something!
Just joking... The two links are in the right panel anyways...
BTW if I knew your site had these tutorials I wouldn't have cracked my head to discover how to do box-box collision... I know sphere-sphere also but discovering sphere-box collision code has been a real pain.
(And I haven't discovered it yet!)
Oh, and why aren't these tutorials here at VBGamer? It would have saved a lot of my brain! |
Whatever. Who knows... |
Edited by - VBBR on Apr 06 2004 11:04:21 AM |
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Spodi
Warrior
USA
142 Posts |
Posted - Apr 05 2004 : 10:36:02 PM
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Holy crap... thanks for metioning that VBBR, never noticed Peter had those links on his sig, I couldn't find them/too lazy to find them. :)
Btw, Peter, the Talos Studios link dun be working, says Forbidden. WHY DOES NOONE ACCEPT ME!    |
vbGORE |
Edited by - Spodi on Apr 05 2004 10:42:27 PM |
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VBBR
Moderator
Brazil
617 Posts |
Posted - Apr 06 2004 : 11:03:31 AM
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Btw, Peter, the Talos Studios link dun be working, says Forbidden. WHY DOES NOONE ACCEPT ME!
Funny that is. The link works for me.
Maybe the thing is you, really... 
Oh and I will correct my last post, now I have seen the visible orthographic errors... |
Whatever. Who knows... |
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Spodi
Warrior
USA
142 Posts |
Posted - Apr 06 2004 : 5:56:52 PM
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| Okay, it's working now. |
vbGORE |
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VBBR
Moderator
Brazil
617 Posts |
Posted - Apr 08 2004 : 10:38:48 AM
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| Hey, not to take this up again, but... The 'Latest' part on the left column of the site is completely empty, why not change it to 'Latest Topics' ? |
Whatever. Who knows... |
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Eric Coleman
Gladiator
USA
811 Posts |
Posted - Apr 08 2004 : 12:13:17 PM
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The "Latest" refers to all the sections underneath, such as "Latest Headlines", "Latest Links", "Latest Tutorial." Putting the word "Latest" on each section would be repetivite, and it wouldn't fit either. Hopefully Peter will be inspired to create a new layout soon.  |
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VBBR
Moderator
Brazil
617 Posts |
Posted - Apr 08 2004 : 12:43:26 PM
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Oh got it. Hum, then I guess it's all up to Peter then.
(BTW, I didn't knew Peter was responsible by the layout)
But then why not put a "Topics" among the "Headlines", "Links", "Tutorials" ? |
Whatever. Who knows... |
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Little suggestion
