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calculus test 1 FAILURE

Posted: Thu Nov 10, 2005 6:44 am
by shiznatix
ok so i just bombed this test, no worries it does not count for me but still i need to know what is going on. here was the function we where given:

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(x-1)^3
y = ----------
      (x+1)^2
here where the questions

1) Find the domain of the function (got this one correct, the only one i got right)
2) Find the discontinuities
3) Find the zeros of the function
4) Is the function odd or even

__this is where it starts getting even more tricky becuase there was a lot of blank space on the paper so i know we where supposed to write a lot__

5) Find intervals on which the function is positive or negative
6) Find local maxima and minima and intervals on which the curce is increading or decreasing (maybe her english is not good enough to translate this to me properly?)
7)Find the points of inflection and intervals on which the curve is concave upward or downward
8)Asymptotes
a) Vertical asymptotes
b) Oblique asymptotes

I have no idea about any of those except the first one, if you can help me out on any of them then I will be very happy with you. thanks.

Posted: Thu Nov 10, 2005 6:57 am
by Charles256
discontinuity at -1, zero at 1. function is odd (an odd and an even make an odd in functions too,don't htey?)
and unless memory fails me you need to take second and third derivatives to get that paticular information...gotta take a derivative and then plug it into a sign table and note when the sign goes from positive to negative and that gives you certian information..refer to your book?:-D I finished up with Calc. last year so I'm a bit fuzzy...

Posted: Thu Nov 10, 2005 7:01 am
by Charles256
BTW, I think on the first derivative sign chart when you get a sign change you get your max and min. max when sign changes from pos. to neg. and a min when from neg. to pos. of course this is all being pulled out of cobwebs..but hey..can't say I didn't try.. :-D

Posted: Thu Nov 10, 2005 7:01 am
by shiznatix
can you give a little explination as to this discontinuity and odd/even part? i don't see where it comes from

Posted: Thu Nov 10, 2005 7:02 am
by Charles256
plug in x=-1, note how you get a zero in the bottom? and you can't have division by zero:-D so that's a dicontinuity. if you plug in x=1 you get a zero in the top whyich means the entire thing will be zero. i get the odd and eveness by the power x is raised too. in your case x^3, and x^2 on the bottom. and i want to say an odd and an even function of x make an odd but you mgiht want to not quote me on that:-D

Posted: Thu Nov 10, 2005 7:45 am
by shiznatix
ah ok the discontinuity makes perfect sence now. the other part i still don't see where you are coming from. i think i tried that way but i got it wrong, maybe becuase i did not show enough work?

Posted: Thu Nov 10, 2005 7:55 am
by Charles256
i could be wrong;) what cal book aer you using?

Posted: Thu Nov 10, 2005 7:56 am
by shiznatix
Charles256 wrote:i could be wrong;) what cal book aer you using?
im not. they don't teach out of a book here in college, its all done though lectures and practice

Posted: Thu Nov 10, 2005 9:16 am
by Charles256
well damn.don't ya take notes?:-D

Posted: Thu Nov 10, 2005 9:58 am
by Moocat
Charles256 wrote:well damn.don't ya take notes?:-D
Lecture + Practice - Book + Notes = Pass

Lecture + Practice - Book - Notes = Fail

There's some math for ya ;)

Posted: Thu Nov 10, 2005 11:21 am
by Weirdan
shiznatix wrote:ah ok the discontinuity makes perfect sence now. the other part i still don't see where you are coming from. i think i tried that way but i got it wrong, maybe becuase i did not show enough work?
if

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f(-x) = f(x)
then function f is said to be 'even'

if

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f(-x) = -f(x)
then function f is said to be 'odd'

Posted: Thu Nov 10, 2005 11:24 am
by Charles256
bam.tha'ts it:-D

Posted: Thu Nov 10, 2005 7:35 pm
by shiznatix
Weirdan wrote:
shiznatix wrote:ah ok the discontinuity makes perfect sence now. the other part i still don't see where you are coming from. i think i tried that way but i got it wrong, maybe becuase i did not show enough work?
if

Code: Select all

f(-x) = f(x)
then function f is said to be 'even'

if

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f(-x) = -f(x)
then function f is said to be 'odd'
i am very sorry but that makes no sence to me. if you can explain a bit more then i would bear your first born son (if physically possible) just to show how much i care. can you show some examples????

Posted: Thu Nov 10, 2005 8:12 pm
by Weirdan
shiznatix wrote: i am very sorry but that makes no sence to me. if you can explain a bit more then i would bear your first born son (if physically possible) just to show how much i care. can you show some examples????
ok, here are simple examples:

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f(x) = x^2  is even, because
f(-x) = (-x)^2 = x^2 = f(x)

f(x) = x^3 is odd, because
f(-x) = (-x)^3 = -(x^3) = -f(x)
Related links:

Posted: Thu Nov 10, 2005 11:55 pm
by mickd
i haven't learnt calculus yet because they teach it in yr 11 (im in yr 10) (in Australia) but i have done it with my tutor.

off memory.

even functions look identical on both sides when graphed.

odd functions don't.