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# TSR's Penguin Society watch

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you did that on purpose
No i didnt! .... loll
my eyes are hurting but i dont want o go to sleep

np i made mine on there

erm is it about £40?? i cant remember
Lol same and its nearly 4 loll so what time is sunrise? loll

just found out that my biology exam is actually 4 Hours long

loll np
3. (Original post by Angel Interceptor)
Meh, this is what I did:

y = (x2 - 4)3

dy/dx = 6x(x2 - 4)2

d2y/dx2 = 24x2(x2 - 4)

Anyhows, stationary points occur when dy/dx = 0, ie. 0 = 6x(x2 - 4)2, which can be simplified to 0 = 6(x - 2)2 + x(x + 2)2

This gives x values of 2, 0 and 2, and corresponding y values of 0, -64 and -216, so you get the coordinates (2,0), (0,-64) and (-2,-216).
d2/dx2 = 24x2(x2 - 4)

Substituting the x values into the equation for d2y/dx2, we get 0, 0 and 0 (like you got), hence you cannot deduce anything from this apart from that at those coordinates, you have points of inflection. If you don't believe that, then have a look at the graph.

PS. I hate typing out maths! It takes so long!
ah so thats how you do ^2 i know what you mean about typing maths

how can you deduce that they're points of inflexion without drawing a graph- or cant you? ( this is where i got stuck)

btw thanks for the help
4. (Original post by SketchyCanvas)

try to loll
i just did

ok haahahah
ah so thats how you do ^2 i know what you mean about typing maths

how can you deduce that they're points of inflexion without drawing a graph- or cant you? ( this is where i got stuck)
Tsk, n00bs know nothing!

Sketch the graph and see for yourself - it's an easy sketch.
i just did

ok haahahah
well you cant :eviltongu

loll
7. (Original post by Angel Interceptor)
Tsk, n00bs know nothing!

Sketch the graph and see for yourself - it's an easy sketch.

loll
8. (Original post by SketchyCanvas)
No i didnt! .... loll
this isnt over yet
9. (Original post by SketchyCanvas)
Lol same and its nearly 4 loll so what time is sunrise? loll

just found out that my biology exam is actually 4 Hours long

loll np
about sixish i think we have to be asleep before sunrise

4 hours i thought it was 3???

hehe
10. (Original post by SketchyCanvas)
loll
Oh dear, if you're finding that funny, it means that you're in need of some sleep....now!
11. (Original post by Angel Interceptor)
Tsk, n00bs know nothing!

Sketch the graph and see for yourself - it's an easy sketch.
meh, you oldies think you know everything (and i dont want to know if you do )

thanks muchly appreciated- now i can sleep in peace its a funny looking graph!
12. Anyhows, here's the graph if you're being a lazy sod! There are tiny fluctuations at the points of inflection, but it's not noticeable on this scale.

Edit: This graph is actually quite pointless, anyhows the maths you've done shows you that there aren't any localised maxima or minima on it.
13. (Original post by SketchyCanvas)
well you cant :eviltongu

loll
since when? ^o)

this isnt over yet
its over, me win lol
15. (Original post by Angel Interceptor)
Oh dear, if you're finding that funny, it means that you're in need of some sleep....now!
Lol i've gone giggly its cos of the sleepyness, makes me giggly
16. (Original post by SketchyCanvas)
Lol i've gone giggly its cos of the sleepyness, makes me giggly
Well, I prefer cheerful people anyway, so it doesn't bother me.
since when? ^o)

since now loll

18. (Original post by Angel Interceptor)
Anyhows, here's the graph if you're being a lazy sod! There are tiny fluctuations at the points of inflection, but it's not noticeable on this scale.

Edit: This graph is actually quite pointless, anyhows the maths you've done shows you that there aren't any localised maxima or minima on it.
meh im lazy, but not that lazy

so if d^2y/dx =0 its a point of inflexion?

(cant be bothered with the sup thing )
19. (Original post by Angel Interceptor)
Well, I prefer cheerful people anyway, so it doesn't bother me.

oo oo just remebered, can you lot fill this in please http://kevan.org/johari?name=Munise meh, im bored
20. (Original post by SketchyCanvas)
its over, me win lol
its over when i say its over

im on a high aswell i'm trying my bestest to not laugh loudly

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Updated: June 14, 2006
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