trig graphs: modelling & calculations for biorhythmic cycles

[falloutatthedisco]

1. A popular theory that attempts to explain the upps and downs of everyday life states that each of us has three cycles, called biorythyms, which begin at birth. These three cycles can be modeled by sine waves. Physical (23 days): P=sin(2pit/23), t is greater than or equal to 0

Emotional (28 days): E= sin(2pit/28), t is greater than or equal to zero
Intellectual (33 days): I=sin(2pit/33), t is greater than or equal to zero

t is the number of days since birth. consider a person who was born on July 20,1986

use a graphing utility to graph the three models in the same viewing window for 7300<t<7380

describe the person's biorythyms during the month of September 2006

calculate the person's three energy levels on September 22,2006

any and all help is appreciated.... thanks!

 

[Deleted member 4993]

Re: trig graphs...

1. A popular theory that attempts to explain the upps and downs of everyday life states that each of us has three cycles, called biorythyms, which begin at birth. These three cycles can be modeled by sine waves. Physical (23 days): P=sin(2pit/23), t is greater than or equal to 0
Emotional (28 days): E= sin(2pit/28), t is greater than or equal to zero
Intellectual (33 days): I=sin(2pit/33), t is greater than or equal to zero

t is the number of days since birth. consider a person who was born on July 20,1986

use a graphing utility to graph the three models in the same viewing window for 7300<t<7380

describe the person's biorythyms during the month of September 2006

calculate the person's three energy levels on September 22,2006

any and all help is appreciated.... thanks!

duplicate post:

http://www.mathhelpforum.com/math-help/ ... raphs.html

Please show us your work, indicating exactly where you are stuck - so that we know where to begin to help you.

 

[falloutatthedisco]

Re: trig graphs...

I know how to graph them, just not how to make the range what it needs to be. (I'm using a TI84Plus if that helps). Also, how do I know where September 2006 is on the graph? what exactly do I need to plug in to find that? thanks!

 

[fasteddie65]

Re: trig graphs...

"a person who was born on July 20,1986"

"how do I know where September 2006 is on the graph? what exactly do I need to plug in to find that? "

You would figure how many days have elapsed from July 20, 1986 to Sept 22, 2006. You have to figure which years were leap years, and add 1 extra day for those. Then simply substitute the number of days into the equation.

 

[mmm4444bot]

... describe the person's biorythyms during the month of September 2006 ...

Hi Fallout:

If you would like to compare calculations, then here is what I got.

From 07-20-1986 through 09-01-2006 is 7349 days.

From 07-20-1986 through 09-30-2006 is 7379 days.

Agree?

~ Mark