Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Stunaep on March 10, 2004, 01:06:30 pm
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Here's some high-school trigonometry for ya.
1) _____1________ = cosx
1+tanx*tanx/2
2) __sin2x__ *__ cosx__
1+cos2x 1-cosŽ2x
I'll post more, as they come.
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Couple of quick questions...are we just supposed to solve for x? And what is the character next to the cosine in the 2nd equation in the bottom right? Is that a "Z" or is it supposed to mean inverse cosine?
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Sorry about that.
1st equation: prove
2nd equation: simplify
That character is to sign that the '2' next to it, is not supposed to be a 2, but 'to the power of 2'.
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Originally posted by Stunaep
That character is to sign that the '2' next to it, is not supposed to be a 2, but 'to the power of 2'.
The use Z^2. :D
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I would, if I knew where the heck that thing was.
Though Now I can use copy-paste.
So, any actual ideas?
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shift-6
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on an american keyboard. Sucka
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*answers the geek call*
1)
_____1______ = cos x
2_+_tan^2_x <=>
..........2
<=> _____2____ = cos x <=>
.......2 + tan^2 x
because tan^2 + 1 = 1/cox x
<=> _2_cos_x_ = cos x etc...
..............2
gonna do the other one...
*goes to the geek mobile and escapes*
P.S.
In the second what is cos2x (example)? is it cos 2x or cos^2 x?
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Originally posted by Stunaep
on an american keyboard. Sucka
:wtf:
Mine is an american qwerty keyboard. Look at the numbers above the letter section of your keyboard. shift+6 = ^.
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mine is an estonian keyboard. sucka.
Ghostavo: This would be fine and dandy, but the second tangent ain't tan x, but is tan x/2, and thus isn't 1/cosŽ2x.
the best thing I can think of is writing tanx as sinx/cosx, and tanx/2 as (1-cosx)/sinx, but I've no idea where to go from there.
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isn't tan x/2 = tan_x ? ?
....................... 2 ? ?
if so I put the 2 on top thus making it null.... but before I had to multiply the 1 by 2 to stay correct. It correct, I assure you.
:EDIT:
The dots are just to put the numbers into position...
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Ah, but I should have explained myself better.
In tan x/2, the angle x is divided by two. Not the fuction tan x/2.
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Originally posted by Stunaep
mine is an estonian keyboard. sucka.
My apologies then
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In that case all you can do is prove it's false...
Do the reverse of what I did but in the 2nd member so that it stays:
________1_________ = ________1__________
1 + tan x * tan x/2 ...... 1 + tan x * (tan x)/2
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I'm just taking Algebra I....don't think I can help.:D
But you've scared me enough...
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algebra 3 is hard enough... and i have pre-calc next year... :shaking:
Here's a problem from my book:
Find all the zeros of the polynomial function:
f(x)=x^4+4x^3-6x^2-36x-27
And for the hell of it, i'll do it out...
Possible zeros are: ±1 ±27 ±3 ±9
....| x^4 +4x^3 -6x^2 -36x -27
.-3|..1......4.......-6........-36...-27
....|.........-3.......-3.........27...27
........1.....1.......-9..........-9.....0
....| x^3 +x^2 -9x -9
-1 |1........1......-9..-9
....|..........-1.....0....9
......1.......0......-9...0
So: (x+3)(x+1)(x²-9)
E...Q...U...A...L...S.......
(x+3)(x+1)(x-3)(x+3)
W.I.C.H....M.E.A.N.S:
The graph crosses the x-axis at -1, and +3, bu TOUCHES it at -3...
Yes, I am THAT bored... :blah: They teach us some weird ways to divide now... Long division was better...
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Originally posted by Stunaep
mine is an estonian keyboard. sucka.
Ha! My keyboard has you all beat--
(http://world.std.com/~jdostale/kbd/SpaceCadet1.jpeg)
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Hippo: That's Algebra III? I learned that in Algebra II, mate. There isn't even Algebra III in the US, that I know of.
And synthetic division is actually easier, you just can't use it as often as you might like to.
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apparently, (well, rumor) my school is the only one in the us still seperating that into algebra 3... i doun't personlly belive it... maybe in the area, since the school i used to go to didn't cover algebra 2 untill junior year... its a public school though, so anything could happen... yeah its easier, but its worse seeing people in 6th grade now multiplying stuff diagonally...
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That's Algebra? I learned that this year... hehe :p
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So does that mean im inhuman for starting algebra in 6th grade?
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Gotta love math...I'm taking my last math class EVER next term up here at college. If any of y'all out there want to be engineers, I hope you like math...because you get a lot more of it. I'm no math genius, so you don't have to be super smart at math in order to be a good engineer, but you have to at least be comfortable with it.
The worst math I've ever had the (dis)pleasure of learning deals with combining calculus and trigonometry. I actually like calculus (it's very useful in the real world), but man, when you take trig identities and start putting them in integrals, it's rough. *shudder* Damn trig subs.
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Originally posted by PhReAk
So does that mean im inhuman for starting algebra in 6th grade?
Nag, the offered Pre-Algebra in sixth grade where I'm at, and I don't imagine it'd be that big of a step to put in Algebra (they usually take it in 7th). I do know a girl who's taking Geometry in 7th grade though...
Poor me is stuck taking Algebra in the 8th grade with a perverted teacher.
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Originally posted by PhReAk
So does that mean im inhuman for starting algebra in 6th grade?
Nope :-P... I started with pre-alg in 6th, pre geometry in 7th grade, algebra 1 in 8th grade, geometry in 9th grade, algebra 2 in first semester 10th grade, algebra 3 in second semester 10th grade (now), and in theory my junior year they'll run me through pre calc and calc, then senior year they'll put me through pre-trig and trig...
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Originally posted by Hippo
in theory my junior year they'll run me through pre calc and calc, then senior year they'll put me through pre-trig and trig...
That seems a little bit backwards to me. Trigonometry plays a critical role with antidifferential/integral calculus (assuming you get that far) so you may want to ask if you can switch those around in your schedule...
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i may have it backwards yet too, since we havent filled out course selections forms for next year yet...