[Stunaep]

Here's some high-school trigonometry for ya.

Code: [Select]


1)     _____1________  = cosx
        1+tanx*tanx/2

2)    __sin2x__  *__ cosx__
      1+cos2x       1-cosŽ2x


I'll post more, as they come.

[jbond04]

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?

[Stunaep]

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'.

[HotSnoJ]

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.

[Stunaep]

I would, if I knew where the heck that thing was.

Though Now I can use copy-paste.

So, any actual ideas?

[DragonClaw]

shift-6

[Stunaep]

on an american keyboard. Sucka

[Ghostavo]

*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?

[HotSnoJ]

Originally posted by Stunaep
on an american keyboard. Sucka

Mine is an american qwerty keyboard. Look at the numbers above the letter section of your keyboard. shift+6 = ^.

[Stunaep]

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.

[Ghostavo]

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...

[Stunaep]

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.

[HotSnoJ]

Originally posted by Stunaep
mine is an estonian keyboard. sucka.

My apologies then

[Ghostavo]

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

[Solatar]

I'm just taking Algebra I....don't think I can help.

But you've scared me enough...

[Hippo]

algebra 3 is hard enough... and i have pre-calc next year...


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... They teach us some weird ways to divide now... Long division was better...

[ZylonBane]

Originally posted by Stunaep
mine is an estonian keyboard. sucka.

Ha! My keyboard has you all beat--

[DragonClaw]

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.

[Hippo]

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...

[Ghostavo]

That's Algebra? I learned that this year... hehe