Math Help!

2008-01-28 20:37:37

#1

TrueMusou: Member; +36|6646|United States Of Hamerica

Okay...this has been racking my head for nearly a day.

I have to reduce f(x) = (x^2-1/x+5 ) - (x+1)/(x-1)

I think I solved it alright and I ended up with (x+1)(x-1)(-x-1)
...but then again, when it comes to math, I'm a g'damn moron.

Anyways, the second part of the question asks for all the values of x where the function has an asymptote.
THERE's NO DENOMINATOR AFTER I FACTORED AND SIMPLIFIED, how is there an asymptote?! So this makes me think that I factored incorrectly.

Also it then asks for the Values of x where f(x) = 0....according to the simplified form I got, I'm gonna get -1, 1, and -1!?!?! can I have two -1?

Then it asks for me to graph...I have no idea.

Someone who knows how to do this help me out...I promise not to come on here with this homework crap anymore.
But this is desperation....

2008-01-28 20:42:28

#2

some_random_panda: Flamesuit essential; +454|6876

Yes, -1 can be a turning point.

And if that's the equation, then it's a cubic.

Like this:
o
o
oo o
o o o
o o o
o oo
o

You get the idea.

EDIT: You probably got it wrong though, a cubic has no asymptotes.

Last edited by some_random_panda (2008-01-28 20:45:04)

2008-01-28 20:46:37

#3

TrueMusou: Member; +36|6646|United States Of Hamerica

some_random_panda wrote:
EDIT: You probably got it wrong though, a cubic has no asymptotes.

Yeah, I think I did something wrong in the factoring....
If someone whose confident with this stuff factor the equation so I can see where I did it wrong...cause I've refactored several times now only to get the same answer.

2008-01-28 20:49:06

#4

CommieChipmunk: Member; +488|7055|Portland, OR, USA

Do you have a graphing calculator?

Plug in the original f(x) and then your simplified f(x) and see if you get the same graph

If you don't just plug in f(1), f(5) and f(8) (or whatever) and see if you get the same values... if you get the same graph/values than you simplified it correctly, if you don't... than you messed up somewhere

2008-01-28 20:49:22

#5

RandomSchl: |\/|€|\/|ß€|2; +52|6929|California

here it is on my calculator, tell me if I typed it in wrong:

https://farm3.static.flickr.com/2039/2227965402_94e3b6a8d0.jpg?v=0

2008-01-28 20:53:00

#6

some_random_panda: Flamesuit essential; +454|6876

RandomSchl wrote:
here it is on my calculator, tell me if I typed it in wrong:

http://farm3.static.flickr.com/2039/222 … d0.jpg?v=0

Is the x^2 meant to be over x as well?

The brackets are somewhat ambiguous.

Last edited by some_random_panda (2008-01-28 20:53:45)

2008-01-28 20:53:04

#7

TrueMusou: Member; +36|6646|United States Of Hamerica

RandomSchl wrote:
here it is on my calculator, tell me if I typed it in wrong:

http://farm3.static.flickr.com/2039/222 … d0.jpg?v=0

This first part is incorrect, it's supposed to be:

x power of 2....minus....1 (numerator) over x + 5 (denominator)

2008-01-28 20:57:12

#8

RandomSchl: |\/|€|\/|ß€|2; +52|6929|California

is this it then:

https://farm3.static.flickr.com/2003/2227979518_42e23d899d.jpg?v=0

lol, I can just keep helping you since I have nothing to do for an hour.

Last edited by RandomSchl (2008-01-28 20:57:58)

2008-01-28 20:57:49

#9

some_random_panda: Flamesuit essential; +454|6876

RandomSchl wrote:
is this it then:

http://farm3.static.flickr.com/2003/222 … 9d.jpg?v=0

No, the X^2 over the X+5

2008-01-28 20:58:32

#10

TrueMusou: Member; +36|6646|United States Of Hamerica

some_random_panda wrote:
RandomSchl wrote:
is this it then:

http://farm3.static.flickr.com/2003/222 … 9d.jpg?v=0
No, the X^2 over the X+5

lol ditto

2008-01-28 20:59:31

#11

some_random_panda: Flamesuit essential; +454|6876

By the way, the asymptotes for the graph would be -5 and 1.

*I think - I'm not putting too much effort into my working.

2008-01-28 21:00:34

#12

RandomSchl: |\/|€|\/|ß€|2; +52|6929|California

ok tell me if I got it right now, its hard to read problems like this without using special formatting.

https://farm3.static.flickr.com/2197/2227984530_1a8c2b32ba_m.jpg

2008-01-28 21:03:09

#13

TrueMusou: Member; +36|6646|United States Of Hamerica

RandomSchl wrote:
ok tell me if I got it right now, its hard to read problems like this without using special formatting.

http://farm3.static.flickr.com/2197/222 … 32ba_m.jpg

Yeah that's it. I plotted the function onto an online graphing calculator (i don't have a real life one)....

I saw the graph...but I dunno how I messed up on the factoring.

2008-01-28 21:04:46

#14

RandomSchl: |\/|€|\/|ß€|2; +52|6929|California

TrueMusou wrote:
RandomSchl wrote:
ok tell me if I got it right now, its hard to read problems like this without using special formatting.

http://farm3.static.flickr.com/2197/222 … 32ba_m.jpg
Yeah that's it. I plotted the function onto an online graphing calculator (i don't have a real life one)....

I saw the graph...but I dunno how I messed up on the factoring.

No graphing calculator? What math are you in? I know in high school graphing calculators are pretty much a must.

2008-01-28 21:11:06

#15

TrueMusou: Member; +36|6646|United States Of Hamerica

RandomSchl wrote:
TrueMusou wrote:
RandomSchl wrote:
ok tell me if I got it right now, its hard to read problems like this without using special formatting.

http://farm3.static.flickr.com/2197/222 … 32ba_m.jpg
Yeah that's it. I plotted the function onto an online graphing calculator (i don't have a real life one)....

I saw the graph...but I dunno how I messed up on the factoring.
No graphing calculator? What math are you in? I know in high school graphing calculators are pretty much a must.

I'm taking Calc...and I barely placed into it (cut off for placement exam was 31....I got 30 the first time...retook it to get a massive score of 31).

This is just algebra crap....show me this stuff 3 years ago, I can crank through it easily. But after the math hibernation I went through Junior and Senior year...I've got none left.

I also don't have one cause the Teacher doesn't allow them for exams.

Also, did your calculator factor the expression? What did it get?

Last edited by TrueMusou (2008-01-28 21:13:28)

2008-01-28 21:48:36

#16

TrueMusou: Member; +36|6646|United States Of Hamerica

I dunno why the thread died...cause i still can't factor the numerator correctly to match the graph.

Someone help please

2008-01-29 10:44:47

#17

S.Lythberg: Mastermind; +429|6932|Chicago, IL

allright, in its simplest form, it becomes: x⁴-x³+4x²-5x+1
x²-x

based on the denominator, there are asymptotes at x=0 and x=1.

the whole equation simplifies to x² + 4 - 1/x

hopefully that helped, as my math thread probably killed yours...

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