Home | Community | Message Board


This site includes paid links. Please support our sponsors.


Welcome to the Shroomery Message Board! You are experiencing a small sample of what the site has to offer. Please login or register to post messages and view our exclusive members-only content. You'll gain access to additional forums, file attachments, board customizations, encrypted private messages, and much more!

Shop: Myyco.com Golden Teacher Liquid Culture For Sale   Kraken Kratom Red Vein Kratom

Jump to first unread post Pages: 1 | 2 | Next >  [ show all ]
OfflinephEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 5 months
urgent math problem i need help getting solved
    #3999264 - 04/01/05 08:46 AM (19 years, 1 day ago)

Hello all, this problem has been cauing me to pull my bloody hairs out..

Naturalists find that the poplulations of some kinds of predatory animals vary periodically. Assume that the population of foxes in a certain forest varies sinusoidally with time. Records started being kept when time t = 0. A minimum number, 200 foxes, occured when t = 2.9 years. The next maximum, 800 foxes, occured at t = 5.1 years.

a.) Sketch a graph of this sinuoid.
b.) Write an equation expressing the number of foxes as a function of time,
t.
c.) Predict the population when t = 7
d.) Foxes are declared to be an endangered species when their population drops below 300. Between what two non-negative values of t were foxes first endangered?

I do not know how this graph should look like... as in whether it should be sine or cosine, and how I would properly show the minimums and maximums. Any help with any aspect of this problem would be greatly appreciated, thanks.


--------------------
"Is it so bad, then, to be misunderstood? Pythagoras was misunderstood, and Socrates, and Jesus, and Luther, and Copernicus, and Galileo, and Newton, and every pure and wise spirit that ever took flesh. To be great is to be misunderstood." -Ralph Waldo Emerson

Extras: Filter Print Post Top
InvisibleBoom
just a tester
Male
Registered: 06/16/04
Posts: 11,252
Loc: Cypress Creek
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999277 - 04/01/05 08:50 AM (19 years, 1 day ago)

Damn! I just had a quiz on this yesterday...give me few minutes

Extras: Filter Print Post Top
OfflinephEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 5 months
Re: urgent math problem i need help getting solved [Re: Boom]
    #3999288 - 04/01/05 08:52 AM (19 years, 1 day ago)

thanks man


--------------------
"Is it so bad, then, to be misunderstood? Pythagoras was misunderstood, and Socrates, and Jesus, and Luther, and Copernicus, and Galileo, and Newton, and every pure and wise spirit that ever took flesh. To be great is to be misunderstood." -Ralph Waldo Emerson

Extras: Filter Print Post Top
OfflineAnnom
※※※※※※
 User Gallery

Folding@home Statistics
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 7 days
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999293 - 04/01/05 08:54 AM (19 years, 1 day ago)

>>as in whether it should be sine or cosine.

They are the same.... translate the sine along the x axis and it will be a cosine.

sin(x)=cos(x+0.5pi)

Extras: Filter Print Post Top
InvisibleBoom
just a tester
Male
Registered: 06/16/04
Posts: 11,252
Loc: Cypress Creek
Re: urgent math problem i need help getting solved [Re: Annom]
    #3999328 - 04/01/05 09:05 AM (19 years, 1 day ago)

Damn I had trig last semester, can't remember shit... :frown:

As Annom said, you can write two equations, one with sin or cosine, and they;ll both be 100% right, just that the sin starts at the origin, and the cosine starts at the maximum, and falls.

Sin=cosine, just cosine is shifted half a period to the left

I forget how to make formuals, but you have everything you need...

The graph is shifted up so that the max is 800 and the min is 200, so I think in the equation the max would be 300??

I'm sorrrry :shrug:

Extras: Filter Print Post Top
OfflineAnnom
※※※※※※
 User Gallery

Folding@home Statistics
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 7 days
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999343 - 04/01/05 09:09 AM (19 years, 1 day ago)

number of foxes(t) = 300*cos[pi/2.2(t-5.1)]+500

Extras: Filter Print Post Top
OfflinephEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 5 months
Re: urgent math problem i need help getting solved [Re: Boom]
    #3999347 - 04/01/05 09:10 AM (19 years, 1 day ago)

It's alright, thanks for tryin though.

How do you figure the equation to be 300? I haven't done this shit in a few months and all of a sudden we have a few problems to do as "project" thing, and this was one of them... due in 1 hour =X

For the graph, would the 200 as the minimum go below the line? I mean, doesn't the horizontal line represent 0? So it wouldn't make much sense for it to be below it. Now my question is, if it's not below it, then how am I properly supposed to draw the sin/cosine curve? I'm havin a damn hard time with this problem.

|
|
|------------------------
|
|


--------------------
"Is it so bad, then, to be misunderstood? Pythagoras was misunderstood, and Socrates, and Jesus, and Luther, and Copernicus, and Galileo, and Newton, and every pure and wise spirit that ever took flesh. To be great is to be misunderstood." -Ralph Waldo Emerson

Extras: Filter Print Post Top
InvisibleBoom
just a tester
Male
Registered: 06/16/04
Posts: 11,252
Loc: Cypress Creek
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999351 - 04/01/05 09:11 AM (19 years, 1 day ago)

I got 200 for t=7, might be wrong tho

Dammit today is my day off from brain activity

Extras: Filter Print Post Top
OfflineAnnom
※※※※※※
 User Gallery

Folding@home Statistics
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 7 days
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999378 - 04/01/05 09:17 AM (19 years, 1 day ago)

number of foxes(t) = 300*cos[pi/2.2(t-5.1)]+500

It's hard for me to explain it in English.

The amplitude is increased by a factor 300; that's why every outcome of a normal cos has to be multiplied by 300.

The max for cos(x) is at x=0 and now it should be at 5.1; this is a translation along to x axis to the right, thus t-5.1 .

The period is 2*(5.1-2.9) = 4.4 and the normal period of cos(x) is 2pi. The period is thus increased with a factor 2pi/4.4.

And the middle point of the cos is translated along the y axis and should now be 500; thus the outcome +500.

Extras: Filter Print Post Top
OfflinephEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 5 months
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999384 - 04/01/05 09:18 AM (19 years, 1 day ago)

thanks for the equation annom

booooom, do you mind explaining how you got 200 for t = 7?


--------------------
"Is it so bad, then, to be misunderstood? Pythagoras was misunderstood, and Socrates, and Jesus, and Luther, and Copernicus, and Galileo, and Newton, and every pure and wise spirit that ever took flesh. To be great is to be misunderstood." -Ralph Waldo Emerson

Extras: Filter Print Post Top
Offlinecybrbeast
Up, then down, then...
Male User Gallery

Folding@home Statistics
Registered: 01/06/03
Posts: 4,777
Loc: event horizon
Last seen: 7 years, 10 months
Re: urgent math problem i need help getting solved [Re: Annom]
    #3999386 - 04/01/05 09:19 AM (19 years, 1 day ago)

I arrived at the same conclusion only I have
foxes(t) = 300*cos[pi/2.2(t-0.7)]+500

Extras: Filter Print Post Top
Offlinecybrbeast
Up, then down, then...
Male User Gallery

Folding@home Statistics
Registered: 01/06/03
Posts: 4,777
Loc: event horizon
Last seen: 7 years, 10 months
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999391 - 04/01/05 09:20 AM (19 years, 1 day ago)

The population for t=7 is ~227

Extras: Filter Print Post Top
InvisibleBoom
just a tester
Male
Registered: 06/16/04
Posts: 11,252
Loc: Cypress Creek
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999394 - 04/01/05 09:20 AM (19 years, 1 day ago)

I wrote some shitty little graph

800 as the max, 200 as the min, where the x axis intercepts the y I called this 500.

Then I put 5.1 as the end of the period (where the max is hit) then i blah blah blah


Do what Annom said :grin:

Extras: Filter Print Post Top
OfflineAnnom
※※※※※※
 User Gallery

Folding@home Statistics
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 7 days
Re: urgent math problem i need help getting solved [Re: cybrbeast]
    #3999403 - 04/01/05 09:23 AM (19 years, 1 day ago)

Quote:

cybrbeast said:
I arrived at the same conclusion only I have
foxes(t) = 300*cos[pi/2.2(t-0.7)]+500




That's just one peroid(4.4) less to the right; it's the same....

Extras: Filter Print Post Top
OfflineAnnom
※※※※※※
 User Gallery

Folding@home Statistics
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 7 days
Re: urgent math problem i need help getting solved [Re: cybrbeast]
    #3999406 - 04/01/05 09:24 AM (19 years, 1 day ago)

Quote:

cybrbeast said:
The population for t=7 is ~227


  :thumbup:

Would you like to smoke my new Hookah with me tonight?  :cool:

Extras: Filter Print Post Top
OfflinephEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 5 months
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999410 - 04/01/05 09:25 AM (19 years, 1 day ago)

lol werd

cyberbeast, can you please tell me how you got t-0.7? your equation is identical to that of annoms except for that...

also, can you please explain to me how you got ~227 for t = 7?

tahnks again guys for helpin me out!


--------------------
"Is it so bad, then, to be misunderstood? Pythagoras was misunderstood, and Socrates, and Jesus, and Luther, and Copernicus, and Galileo, and Newton, and every pure and wise spirit that ever took flesh. To be great is to be misunderstood." -Ralph Waldo Emerson

Extras: Filter Print Post Top
Offlinecybrbeast
Up, then down, then...
Male User Gallery

Folding@home Statistics
Registered: 01/06/03
Posts: 4,777
Loc: event horizon
Last seen: 7 years, 10 months
Re: urgent math problem i need help getting solved [Re: Annom]
    #3999411 - 04/01/05 09:25 AM (19 years, 1 day ago)

Most definately  :grin:

Extras: Filter Print Post Top
Offlinecybrbeast
Up, then down, then...
Male User Gallery

Folding@home Statistics
Registered: 01/06/03
Posts: 4,777
Loc: event horizon
Last seen: 7 years, 10 months
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999420 - 04/01/05 09:27 AM (19 years, 1 day ago)

Annom already gave the answer
Maybe this site will help you
http://math.la.asu.edu/~walker/mat170/homework/sine_curves.htm

t=7
foxes(t) = 300*cos[pi/2.2(7-0.7)]+500 = 227.1104 etc

Extras: Filter Print Post Top
OfflineAnnom
※※※※※※
 User Gallery

Folding@home Statistics
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 7 days
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999433 - 04/01/05 09:30 AM (19 years, 1 day ago)

Quote:

phEight said:
lol werd

cyberbeast, can you please tell me how you got t-0.7? your equation is identical to that of annoms except for that...

also, can you please explain to me how you got ~227 for t = 7?

tahnks again guys for helpin me out!




A cosine is 'duplicated' every one period. The equation gives the same outcome at x+one period. The period of foxes(t) is 4.4. So 300*cos[pi/2.2(t-0.7)]+500 and 300*cos[pi/2.2(t-5.1)]+500 and 300*cos[pi/2.2(t-9.5)]+500 are all the same.

foxes(7)=300*cos[pi/2.2(7-0.7)]+500 = 227.11

Extras: Filter Print Post Top
Offlinecybrbeast
Up, then down, then...
Male User Gallery

Folding@home Statistics
Registered: 01/06/03
Posts: 4,777
Loc: event horizon
Last seen: 7 years, 10 months
Re: urgent math problem i need help getting solved [Re: phEight]
    #3999439 - 04/01/05 09:31 AM (19 years, 1 day ago)

Between t=2.311 and t=3.489 the foxes were first endangered.

Extras: Filter Print Post Top
Jump to top Pages: 1 | 2 | Next >  [ show all ]

Shop: Myyco.com Golden Teacher Liquid Culture For Sale   Kraken Kratom Red Vein Kratom


Similar ThreadsPosterViewsRepliesLast post
* Let's see if you guys can solve a math problem... :D
( 1 2 all )
Cerius 2,757 20 07/14/08 03:27 PM
by DieCommie
* New math! Tedwilto 683 15 12/23/08 02:22 PM
by k4ge
* make math interesting......
( 1 2 all )
DistortedEyes 2,222 29 04/07/06 06:24 AM
by BioBunny
* Pi-3.14 Phishe 727 16 02/05/07 11:07 PM
by Turn
* Missed lecture today, need help with Diff Eq Laplace transform HW problem. friedmeat 320 1 03/03/09 05:17 PM
by friedmeat
* I NEED THE MATH WIZARDS HELP norml840 387 10 05/10/09 05:04 PM
by norml840
* PI is a good movie {Math, the language of nature} I liked it a lot, how about you? Rahie 700 5 02/26/07 08:07 PM
by SymmetryGroup8
* having a brain fart here(maths)... DistortedEyes 654 9 11/07/06 02:43 PM
by sleepy

Extra information
You cannot start new topics / You cannot reply to topics
HTML is disabled / BBCode is enabled
Moderator: Entire Staff
2,765 topic views. 10 members, 83 guests and 99 web crawlers are browsing this forum.
[ Show Images Only | Sort by Score | Print Topic ]
Search this thread:

Copyright 1997-2024 Mind Media. Some rights reserved.

Generated in 0.024 seconds spending 0.005 seconds on 14 queries.