
#201




Re: Things You Just Don't Get In Math Class
If someone could help me with this I'd love them forever. OK the question is:
Show that for theta being real, Re(e to the power i theta / i + e to the power i theta) is independent of theta. And now I've realised my love of symbols! I hope that makes sense to someone. I know it's a bit of a long shot but ah well. 
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#202




Re: Things You Just Don't Get In Math Class
ARGH I HATE MATHS! XD
There are tons of things I don't get! But decimals are my worst enemy... stuff like rounding them up, fractions to do with decimals... algebra and gah, yeah. Lots of stuff. But basically decimals are hell. 
#203




Re: Things You Just Don't Get In Math Class
Quote:
You want the real part of (e^iT)/(i+e^iT). 1. Euler's Law tells us that e^iT = cos(T )+ i*sin(T). I'm gonna drop those parens, to keep it neater. So, (e^iT)/(i+e^iT) = (cosT + i*sinT) / (i + cosT + i*sinT) 2. Rearrange the denominator to give you an a+bi form: (cosT + isinT)) / (cosT + (1+sinT)i) 3. Multiply both the numerator and the denominator by the conjugate of the denominator. (That means, take that a+bi on the bottom, and multiply the whole thing by (abi)/(abi) (cosT+ isinT) * (cosT(1+sinT)i) / (cosT+(1+sinT)i)*(cosT(1+sinT)i) 4. Simplify. The denominator is easy, because (abi)(a+bi)= a^2 + b^2. The numerator, I think you just have to multiply it all out. cosT^2+icosTsinTicosT(1+sinT)+sinT(sinT+1) / cosT^2+(sinT+1)^2 5. Simplify further multiplying out anything still to multiply cosT^2+icosTsinTicosTicosTsinT+sinT^2+sinT/cosT^2+sinT^2+1+2sinT 6. Well, lookee there, I've got some things cancel each other out! Simplify still further. cosT^2icosT+sinT^2+sinT/cosT^2+sinT^2+1+2sinT 7. Remember that cosT^2+sinT^2=1 for any real T. 1icosT+sinT / 1+1+2sinT 8. Let's get all our like terms combined again and get the numerator back into that a+bi form. 1+sinTicosT / 2+2sinT 9. Any time you have a fraction, (cd)/z = c/z  d/z. So, ((1+sinT) / (2+2sinT))  icosT/ (2+2sinT) 10. We only care about the real part, so we can drop that last fraction. Re(((1+sinT) / (2+2sinT))  icosT/ (2+2sinT)) = 1+sinT / 2+2sinT 11. Factor a 2 out of the denominator 1+sinT / 2(1+sinT) 12. Cancel the 1+sinT's. 1 / 2. So, for any real T, Re(e^iT)/(i+e^iT) = 1/2. Whew, that may be impossible to read without symbols.... Hope it helped. 
#204




Re: Things You Just Don't Get In Math Class
My eyes are going all funny!
Thanks for that, I had a flash of inspiration on the train and managed to figure it all out. Good thing I got the same answer as you. 
#205




Re: Things You Just Don't Get In Math Class
And that's from WHAT Math class? I got lost trying to comprehend it.
For me, when I don't get what my math teacher is saying, I just space out by playing that Puzzle Pack game thingy on the school's calculators. 
#206




Re: Things You Just Don't Get In Math Class
Well I'm doing it in a first year maths course at university (I'm actually in second year but needed a subject, why I chose maths I'll never know) but you could do that sort of stuff in an advanced maths class at secondary school.

#207




Re: Things You Just Don't Get In Math Class
Quote:
It would be much easier to comprehend written with actual math symbols and spacing.... Glad you got it on your own UAM  I'm a math geek, I actually enjoyed figuring that out! 
#208




Re: Things You Just Don't Get In Math Class
My only real problem with maths is that I can't just accept something. I always want to know why this is like this and why that. I want them to prove to me where they are getting it all from. So it means I spend longer trying to figure that out than the actual problems.

#209




Re: Things You Just Don't Get In Math Class
I think I would have learnt a lot more in math class if it wasn't for those games!

#210




Re: Things You Just Don't Get In Math Class
Quote:
Block Dude=Level 6(I can't figure out how to solve Level 7) Pegs=Level 10 or so Dino Puzzle=I HATE THIS ONE. I never play it. That other one= Endless Mode=score of 2500 or so Puzzle Mode=Level 13 
#211




Re: Things You Just Don't Get In Math Class
Sinusoidal functions are my kryptonite. Urgh
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#212




Re: Things You Just Don't Get In Math Class
Quote:
Anywho back on topic, in Calculus, I always struggled with integration. I was okay with differentiation but I found integration a lot harder to grasp. I hated those problems where you had to find the area under/over/around a curve. They drove me mental. 
#213




Re: Things You Just Don't Get In Math Class
Finally I'm starting to get what my teacher's teaching in Algebra II.
But, that doesn't mean I can't stop playing Block Dude. 
#214




Re: Things You Just Don't Get In Math Class
I don't get long division when there's an X variable in it. Like this:
(x  3) / (9x^2 + 6x + 15) I can only doing it using synthetic division. Long division of this stuff drives me crazy. I just don't get it.
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~ Stephan King, July 2007 
#215




Re: Things You Just Don't Get In Math Class
Quote:
Here's a link to the solution cause wrote it out...with all the symbols and such. Excuse the bad handwriting, it's not that horrible with a pen and paper instead of a Wacom tablet. I could try to clarify more if the way I explained it is confusing. http://i68.photobucket.com/albums/i2...divofpolys.jpg PS: I really like the song that's in your sig. PPS: Quote:
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Last edited by Kitunen; November 3rd, 2007 at 7:57 pm. 
#216




Re: Things You Just Don't Get In Math Class
One thing that helped me with theta and trig functions is to remember that "Theta" is just a symbol...and it can stand for anything. Even an expression like (X+3Y). We started trig functions around this time of year, too, because I still remember my teacher talking about "sine of pumpkin" and "cosine of pilgrim hat" to help us not be so scared of the greek letters....Good luck!

#217




Re: Things You Just Don't Get In Math Class
Quote:
He also told us the "X^n" functions were the All Blacks, exponential some rocking dude and natural logarithm some arrogant dude who didn't show off as much when the All Blacks were around...
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I DID expect the Spanish Inquisition! 
#218




Re: Things You Just Don't Get In Math Class
I always hated teachers saying things like that, it never helped me at all.
Currently I am hating maths. I seem to figure things out a bit too late for when the tests are but a couple of days after them I know how to do everything. It also doesn't help that some of the questions don't make it very clear (at least to me) what they're wanting me to do. 
#219




Re: Things You Just Don't Get In Math Class
Quote:
What's difficult with math is knowing how to start.
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I DID expect the Spanish Inquisition! 
#220




Re: Things You Just Don't Get In Math Class
Quote:
If someone could tell me what this is question is asking me then that'd be a step in the right direction: By expressing 7Pi/12 as an appropriate sum, find exact expressions for the since and cosine of 7Pi/12. 
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