Exponential or Proportional or Exponentially Proporational?

@if ®afiq · 13 Mar 2006 at 18:36

If a fatty like me was getting bigger as he got older at a set rate, would that be exponential, proporational or exponentially proporational? :confused:

p4radox · 13 Mar 2006 at 18:37

I'd say your weight is directly proportional to your age. If you were ballooning beyond all control, then your weight would be increasing exponentially.

Matblack · 13 Mar 2006 at 18:40

Yep proportional, exponentional would be increasing by twice as much as last time each year, I think :confused:

MB

Greenlizard0 · 13 Mar 2006 at 18:45

exponential would be increasingly increasing...to factors larger than two eventually...

Amleto · 13 Mar 2006 at 18:47

Matblack said:
Yep proportional, exponentional would be increasing by twice as much as last time each year, I think

MB

not necessarily twice, but a constant factor.

if you are gaining x kgs/year then that is linear (proportional to time)

edit: greenlizard, see above

Greenlizard0 · 13 Mar 2006 at 18:56

Amleto said:
edit: greenlizard, see above

pardon?

Amleto · 13 Mar 2006 at 19:02

greenlizard0 said:
pardon?

for exponential change per unit time, the factor is constant.

VIRII · 13 Mar 2006 at 20:07

If you put on 1 stone per year that would be constant growth.
If you put on 10% per year (of the previous years mass) that would also be constant and proportional.
If you put on 10% this year and 20% next year and 40% the year after that would be exponential ie the amount increased is a multiple of the previous amount.

Amleto · 13 Mar 2006 at 22:30

VIRII said:
If you put on 1 stone per year that would be constant growth.
If you put on 10% per year (of the previous years mass) that would also be constant and proportional.
If you put on 10% this year and 20% next year and 40% the year after that would be exponential ie the amount increased is a multiple of the previous amount.

I disagree.

If it was 10% every year, that would be exponential. If it is 10, 20, 30 etc then I don't think that is exponential.

http://highered.mcgraw-hill.com/sites/0070294267/student_view0/glossary_e-l.html

exponential growth Growth at a constant rate of increase per unit of time; can be expressed as a constant fraction or exponent. See geometric growth.

http://www.silcom.com/~barnowl/chain-letter/glossary.htm

Exponential growth. Change in a population that is proportional to the size of the population. If y(t) designates the population at time t, this condition is dy/dt = ky, k a constant called the growth constant. The implies that y = y0 ekt where the constant y0 = y(0) is the population at time t = 0.

Note the constant.

Beansprout · 13 Mar 2006 at 22:32

VIRII said:
If you put on 10% this year and 20% next year and 40% the year after that would be exponential ie the amount increased is a multiple of the previous amount.

That would be an x^2 relationship

(I did A-level maths...does that sound right anyone? Please?

)

Amleto · 13 Mar 2006 at 22:34

Beansprout said:
That would be an x^2 relationship

(I did A-level maths...does that sound right anyone? Please? )

x^2 is very large growth, whereas 10%, 20%, 40% exceeds exponential growth.

You're not squaring anything though - 10% to 20% ...

Beansprout · 13 Mar 2006 at 22:43

Amleto said:
x^2 is very large growth, whereas 10%, 20%, 40% exceeds exponential growth.

You're not squaring anything though - 10% to 20% ...

Edit: Hangon...1^2 = 1, 2^2 = 4....hmm...according to me, 1^2 = 2....bye.

Amleto · 13 Mar 2006 at 22:49

Beansprout said:
Edit: Hangon...1^2 = 1, 2^2 = 4....hmm...according to me, 1^2 = 2....bye.

ahhh. e-hug

Roduga · 14 Mar 2006 at 00:39

So, to sum up: go to the gym!

@if ®afiq · 14 Mar 2006 at 23:18

Roduga said:
So, to sum up: go to the gym!

lol

Thanks for clearing that up peeps

Amleto · 14 Mar 2006 at 23:42

@if ®afiq said:
lol

Thanks for clearing that up peeps

no probs.