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+--- Thread: is this legal? (/showthread.php?tid=3895)
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is this legal? - butterfλi - 2008-10-02
(mathematically)
if cos²(u) + sin²(u) = 1, then does
cos²(2t) + sin²(2t) = 1?
because technically those are double angle formulas (where cos²(2t) = [cos(2t)]².
and if we let u = 2t, then cos²(2t) + sin²(2t) = 1 -> cos²(u) + sin²(u) = 1. but then we cant substitute 2t back in for u since its just a 1 now and nowhere to plug u into.
is this legal? - Derimed - 2008-10-02
No it's not legal, you're gonna get locked up for 25-life.
WHAT YOU HAVE DONE HERE IS A FUCKING FELONY, A MOCKERY OF ALL THAT IS SACRED AND GOOD!!! 
is this legal? - butterfλi - 2008-10-02
relax man. im not quite here yet.
Spoiler
![[Image: 1215066776191tp6.jpg]](http://img136.imageshack.us/img136/6962/1215066776191tp6.jpg)
is this legal? - Derimed - 2008-10-02
butterfli Wrote:relax man. im not quite here yet.
Spoiler
Is that the same black hole our tax dollars go into?
is this legal? - Erich - 2008-10-02
butterfli Wrote:relax man. im not quite here yet.
Spoiler
NOOOOOOOOOOOOOOOOOOOOO
why'd ya have to divide by zero?
is this legal? - butterfλi - 2008-10-02
Quantact Wrote:Is that the same black hole our tax dollars go into?
secretary of US treasury mustve divided by zero.
is this legal? - psychopat - 2008-10-02
If t is a variable and not a function, then yes that's legal.
If t is a function, I'm not 100% sure but I think it's also legal... not sure.
is this legal? - Derimed - 2008-10-02
butterfli Wrote:secretary of US treasury mustve divided by zero.
They shred cash and stuff lamps with it, what did you expect?
is this legal? - butterfλi - 2008-10-02
psychopat Wrote:If t is a variable and not a function, then yes that's legal.
If t is a function, I'm not 100% sure but I think it's also legal... not sure.
the whole problem is (vector) integrating.
i simplified the integral to look like:
inte[sqrt(144(cos²(2t) + sin²(2t)) + 25)]dt
if i did cos²(2t) + sin²(2t) = 1, then it'd look like
inte[sqrt(144(1) + 25)]dt
=inte[sqrt(169)]dt
=inte[13]dt = 13t
the answer and final stepped looked to easy and simple so i wondered if doing that trig thing was legal lol. its suspicious when complicated math problems come out to have simple answers.
is this legal? - Magus - 2008-10-02
No but this is:
Spoiler
![[Image: dividezerowf4.jpg]](http://img528.imageshack.us/img528/1797/dividezerowf4.jpg)
is this legal? - Wani - 2008-10-02
All jokes aside, yeah, that's valid maths.
is this legal? - JoeTang - 2008-10-02
cos²(u) + sin²(u) = 1
Holds valid, as long as the arguments of the trigonometric functions, u, are the same.
So, since u = 2t, it would be true for
cos²(2t) + sin²(2t) = 1
But not true for
cos²(2t) + sin²(3t) = 1
since 2t is not equal 3t (unless t = 0).
And yes, I do believe that is the correct solution for the integral.
is this legal? - Worthyness - 2008-10-02
inte[sqrt(144(cos²(2t) + sin²(2t)) + 25)]dt
What you are doing is u substitution. in order for your theory to be viable, you would have to do the following:
u= 2t --> du = 2 dt
so technically the answer you have is wrong since you did not compensate for the 2dt...
But all the other math workings i can't do, since i'm not in a high level calculus class =P
i.e. no clue how to do this... but you can do the u thingy if you compensate for the dt part...
is this legal? - JoeTang - 2008-10-02
You don't have to do u substitution. cos²(2t) + sin²(2t) = 1.
is this legal? - butterfλi - 2008-10-02
Worthyness Wrote:inte[sqrt(144(cos²(2t) + sin²(2t)) + 25)]dtu was just a random variable. i didnt do u substitution, it was trig substitution/trig identity.
What you are doing is u substitution. in order for your theory to be viable, you would have to do the following:
u= 2t --> du = 2 dt
so technically the answer you have is wrong since you did not compensate for the 2dt...
is this legal? - Stereo - 2008-10-02
13t + c
You'd need a specific solution to know what c is.
is this legal? - Rain - 2008-10-02
I snap. Your getting death row now D:>
QUICK! TO
is this legal? - butterfλi - 2008-10-02
Stereo Wrote:13t + c
You'd need a specific solution to know what c is.
it was a definite integral
2u2thanks to people who answered. people who didnt can go get divided by zero now.
is this legal? - JezzaRules - 2008-10-02
uhh sorry I don't do Specialist Math :f6:
Wow... that looks kinda confusing, shame I only do Methods 3/4
is this legal? - KajitiSouls - 2008-10-02
You know about that 1 over there? I'm pretty sure that means the t's have canceled each other like matter on anti-matter. And you're not doing anything illegal as far as I can tell.