|
 phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
 urgent math problem i need help getting solved 
#3999264 - 04/01/05 08:46 AM (19 years, 20 days 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
|
 Boom
just a tester
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, 20 days ago) |
|
|
Damn! I just had a quiz on this yesterday...give me few minutes
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: Boom]
#3999288 - 04/01/05 08:52 AM (19 years, 20 days 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
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999293 - 04/01/05 08:54 AM (19 years, 20 days 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)
|
Boom
just a tester
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, 20 days ago) |
|
|
Damn I had trig last semester, can't remember shit... 
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 
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999343 - 04/01/05 09:09 AM (19 years, 20 days ago) |
|
|
number of foxes(t) = 300*cos[pi/2.2(t-5.1)]+500
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: Boom]
#3999347 - 04/01/05 09:10 AM (19 years, 20 days 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
|
Boom
just a tester
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, 20 days ago) |
|
|
I got 200 for t=7, might be wrong tho
Dammit today is my day off from brain activity
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999378 - 04/01/05 09:17 AM (19 years, 20 days 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.
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999384 - 04/01/05 09:18 AM (19 years, 20 days 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
|
cybrbeast
Up, then down, then...
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, 20 days ago) |
|
|
I arrived at the same conclusion only I have
foxes(t) = 300*cos[pi/2.2(t-0.7)]+500
|
cybrbeast
Up, then down, then...
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, 20 days ago) |
|
|
The population for t=7 is ~227
|
Boom
just a tester
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, 20 days 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 
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: cybrbeast]
#3999403 - 04/01/05 09:23 AM (19 years, 20 days 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....
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: cybrbeast]
#3999406 - 04/01/05 09:24 AM (19 years, 20 days ago) |
|
|
Quote:
cybrbeast said:
The population for t=7 is ~227
Would you like to smoke my new Hookah with me tonight? 
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999410 - 04/01/05 09:25 AM (19 years, 20 days 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
|
cybrbeast
Up, then down, then...
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, 20 days ago) |
|
|
Most definately
|
cybrbeast
Up, then down, then...
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, 20 days 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
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999433 - 04/01/05 09:30 AM (19 years, 20 days 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
|
cybrbeast
Up, then down, then...
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, 20 days ago) |
|
|
Between t=2.311 and t=3.489 the foxes were first endangered.
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999457 - 04/01/05 09:35 AM (19 years, 20 days ago) |
|
|
thanks a lot dudes... i realy appreciate the help... I think I understand it pretty well now. 
--------------------
"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
|
Shroomism
Space Travellin
Registered: 02/13/00
Posts: 66,015
Loc: 9th Dimension 
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999461 - 04/01/05 09:36 AM (19 years, 20 days ago) |
|
|
the answer is 1.618!!!!!!
--------------------
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
 Re: urgent math problem i need help getting solved [Re: phEight]
#3999473 - 04/01/05 09:38 AM (19 years, 20 days ago) |
|
|
No problem!
Can you help me with a math problem? This is for my exam next friday and I really don't get it:
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999476 - 04/01/05 09:39 AM (19 years, 20 days ago) |
|
|
LOL annom, sure thing... let me get on it.
if anyone could just do a real quick sloppy graph of this graph in paint or something.. that would help confirm would i'm getting.. if not thats cool... i'm gonna be leaving in 10 minutes
--------------------
"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
Edited by phEight (04/01/05 09:40 AM)
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999485 - 04/01/05 09:41 AM (19 years, 20 days ago) |
|
|
I'll make a picture for you!
|
Boom
just a tester
Registered: 06/16/04
Posts: 11,252
Loc: Cypress Creek
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999486 - 04/01/05 09:41 AM (19 years, 20 days ago) |
|
|
How do you take that class without a graphing calc?
|
Annom
※※※※※※
Registered: 12/22/02
Posts: 6,367
Loc: Europe
Last seen: 10 months, 25 days
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999504 - 04/01/05 09:45 AM (19 years, 19 days ago) |
|
|
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#3999531 - 04/01/05 09:51 AM (19 years, 19 days ago) |
|
|
annom, i understand how the curve looks like, however i'm just confused as to how to properly label the x-axis...
800|
|
|
|
500|-------------------------------------
| 2.9 5.1
|
|
200|
at point 500, would the curve jus go down and touch min at 2.9, then go back up and touch max at 5.1?
--------------------
"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
Edited by phEight (04/01/05 09:52 AM)
|
cybrbeast
Up, then down, then...
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]
#3999534 - 04/01/05 09:52 AM (19 years, 19 days ago) |
|
|
Click picture to view
In the window
t goes from 0 to 10
number of foxes from 0 to 800
http://education.bjbarton.com/Calculator.html
|
cybrbeast
Up, then down, then...
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]
#3999544 - 04/01/05 09:53 AM (19 years, 19 days ago) |
|
|
The X axis is usually located at y=0
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: cybrbeast]
#3999562 - 04/01/05 09:58 AM (19 years, 19 days ago) |
|
|
ALRIGHT i got the graph... ONE LAST question.. i promise
how did you get to Between t=2.311 and t=3.489 the foxes were first endangered
yall MUST be sick of me by now 
--------------------
"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
|
cybrbeast
Up, then down, then...
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]
#3999573 - 04/01/05 10:01 AM (19 years, 19 days ago) |
|
|
You can solve the equation
300*cos[pi/2.2(t-0.7)]+500 = 300
Or you can use a graphing calculator if you have it by making it find the point at which the sine crosses with an x=300 line. This is the easy method.
Click
|
cybrbeast
Up, then down, then...
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]
#3999631 - 04/01/05 10:18 AM (19 years, 19 days ago) |
|
|
300*cos[pi/2.2(t-0.7)]+500 = 300
300*cos[pi/2.2(t-0.7)] = -200
cos[pi/2.2(t-0.7)] = -2/3
pi/2.2(t-0.7) = 2.301 or -2.301
pi(t-0.7) = 5.061 or -5.061
t-0.7 = 1.611 or -1.611
t = 2.311 or -0.911
-0.911 is negative so you need to add a period (4.4)
-0.911 + 4.4 = 3.489
|
Shroomism
Space Travellin
Registered: 02/13/00
Posts: 66,015
Loc: 9th Dimension
|
Re: urgent math problem i need help getting solved [Re: cybrbeast]
#3999653 - 04/01/05 10:23 AM (19 years, 19 days ago) |
|
|
look you guys are all wrong.. I'm telling you the answer is 1.618.. believe me I'm a professional mathematician
--------------------
|
phEight
fate
Registered: 06/17/03
Posts: 107
Loc: houston, tx
Last seen: 15 years, 6 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#4000461 - 04/01/05 01:04 PM (19 years, 19 days ago) |
|
|
shroomism, come on now, we ALL know that's not only the answer to the problem, but also the answer to everyyything.
Thanks again guys for all the help.. the least I can do is give you all 5 shrooms!
--------------------
"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
|
freddurgan
Techgnostic
Registered: 01/11/04
Posts: 3,648
Last seen: 11 years, 10 months
|
Re: urgent math problem i need help getting solved [Re: phEight]
#4000960 - 04/01/05 02:27 PM (19 years, 19 days ago) |
|
|
This is funny, cause I go to Georgia Tech, an engineering school where Calculus is supposed to be like...2nd nature, and I have no fucking clue how to solve that problem.
Not a clue. Nadda. None.
|
|
Threaded
Previous
Index
Next
Maeng Da Thai Kratom Leaf Powder 
Certified Organic All-In-One Grow Bags by Magic Bag 
Unfolding Nature: Being in the Implicate Order 
Golden Teacher Liquid Culture For Sale 
Red Vein Kratom
Edit 
Reply 
1 2 all )
Cerius
Tedwilto
DistortedEyes
Phishe
friedmeat
norml840
Rahie