calculus test 1 FAILURE

Ye' old general discussion board. Basically, for everything that isn't covered elsewhere. Come here to shoot the breeze, shoot your mouth off, or whatever suits your fancy.
This forum is not for asking programming related questions.

Moderator: General Moderators

User avatar
shiznatix
DevNet Master
Posts: 2745
Joined: Tue Dec 28, 2004 5:57 pm
Location: Tallinn, Estonia
Contact:

calculus test 1 FAILURE

Post 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:

Code: Select all

(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.
Charles256
DevNet Resident
Posts: 1375
Joined: Fri Sep 16, 2005 9:06 pm

Post 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...
Charles256
DevNet Resident
Posts: 1375
Joined: Fri Sep 16, 2005 9:06 pm

Post 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
User avatar
shiznatix
DevNet Master
Posts: 2745
Joined: Tue Dec 28, 2004 5:57 pm
Location: Tallinn, Estonia
Contact:

Post by shiznatix »

can you give a little explination as to this discontinuity and odd/even part? i don't see where it comes from
Charles256
DevNet Resident
Posts: 1375
Joined: Fri Sep 16, 2005 9:06 pm

Post 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
User avatar
shiznatix
DevNet Master
Posts: 2745
Joined: Tue Dec 28, 2004 5:57 pm
Location: Tallinn, Estonia
Contact:

Post 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?
Charles256
DevNet Resident
Posts: 1375
Joined: Fri Sep 16, 2005 9:06 pm

Post by Charles256 »

i could be wrong;) what cal book aer you using?
User avatar
shiznatix
DevNet Master
Posts: 2745
Joined: Tue Dec 28, 2004 5:57 pm
Location: Tallinn, Estonia
Contact:

Post 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
Charles256
DevNet Resident
Posts: 1375
Joined: Fri Sep 16, 2005 9:06 pm

Post by Charles256 »

well damn.don't ya take notes?:-D
User avatar
Moocat
Forum Contributor
Posts: 143
Joined: Wed Oct 12, 2005 9:28 am
Location: USA

Post 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 ;)
User avatar
Weirdan
Moderator
Posts: 5978
Joined: Mon Nov 03, 2003 6:13 pm
Location: Odessa, Ukraine

Post 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

Code: Select all

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

if

Code: Select all

f(-x) = -f(x)
then function f is said to be 'odd'
Charles256
DevNet Resident
Posts: 1375
Joined: Fri Sep 16, 2005 9:06 pm

Post by Charles256 »

bam.tha'ts it:-D
User avatar
shiznatix
DevNet Master
Posts: 2745
Joined: Tue Dec 28, 2004 5:57 pm
Location: Tallinn, Estonia
Contact:

Post 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

Code: Select all

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????
User avatar
Weirdan
Moderator
Posts: 5978
Joined: Mon Nov 03, 2003 6:13 pm
Location: Odessa, Ukraine

Post 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:

Code: Select all

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:
mickd
Forum Contributor
Posts: 397
Joined: Tue Jun 21, 2005 9:05 am
Location: Australia

Post 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.
Post Reply