IA Type 2 - Viral Illness One

[Gaurang]

Can any one help me with ques 7 of the viral illness portlfolio i am done with the rest but don understand what to do with the last question

thnk u

[Felhound]

Since that other topic is dead, I have to post here.

For question 6 part 2, are they asking how long it takes to recover when the medicine is administered at the latest possible time? or when?

Edited March 22, 2009 by Felhound
Posts merged-Mahuta

[SweRav222]

Hello Everyone

Ok this is my first time using this forum so please forgive me if I have opened this new topic unnecessarily because other topics regarding this ia might have already been posted. I cannot find the other thread to post there so I had to open a new topic because I really need help urgently.

A few days back in my math HL class I got my second IA called: Modelling the Course of a Viral Illness

I have looked at all the questions and even tried half but I need some clarification and help on the following:

For the first part, it says that fever lowers the rate at which viral particles replicate to 160% every four hours. I thought percent increases are always under 100%. I mean even if the viral particles were doubling they would be increasing by 100% every four hours. So where did this 160% come from? Does this sheet assume that when viral particles double, they increase by 200% so the fever basically lowers it to 160% lowering it by 40%?

Secondly, I know this is a common question but I am deeply stuck on #3. I know this question has been asked before several times in other threads and I have gone through those threads many times but I am still confused. I know answers are not allowed and I am not asking for the answers but can anyone guide my though the steps? For #3 I have the equation Y = (YO) 1.6^(t/4) - (1.2 X 10^6)t where Y= number of viral particles in the body at time t, and YO= initial number of viral particles in the body at time t. Is this equation ok? When I differentiated it, as many people in other threads told to use differentiation, I got: dY/dt = (YO) (1/4) 1.6^(-3t/4) - (1.2 X 10^6) Is this ok? If my both original and differential equations are right, then how do I solve for t because right now I have too many unknown variables. Are there any values I am supposed to substitute for t or any other variable?

Lastly I am very confused about the methods needed to solve #4 and #5. My methods seems too easy. I simply decided that the patient will first get injected with a dose of 90 micrograms in the first hour and then for the rest of the 3 hours get injected with 2.5 micrograms of medicine to make up for the 2.5% removed by the kidneys and keep 90 micrograms running. For #5 I simply took the 90 micrograms dose of the first hour, and added (2.5 micrograms) X 3 for the doses of the rest of the three hours to get a total of 98.66 micrograms of dose D given at the beginning of each 4-hour interval to maintain 90 micrograms throughout. Is this the right way or is there any other method?

Please Please help me! My IA is due soon and I would really appreciate your help!

Thanks again everyone! and please excuse my mistakes as this is my first time on this forum! Thanks! Looking forward to your replies!

[SharkSpider]

160% means that it goes from 100% to 160%, effectively a 60% increase. Gotta read these things carefully.

Lastly, in every question you need to consider that these are all continuous functions, and by that regard, none of these questions can be adequately solved without calculus. I can't give any other hint than to set up a differential equation and solve it by hand or with a computer.

[Mahuta ♥]

Theres a thread already for this one, please check before startng a new thread. thanks

[SweRav222]

160% means that it goes from 100% to 160%, effectively a 60% increase. Gotta read these things carefully.

Lastly, in every question you need to consider that these are all continuous functions, and by that regard, none of these questions can be adequately solved without calculus. I can't give any other hint than to set up a differential equation and solve it by hand or with a computer.

thank you. however, i have run into a major issue. i am not allowed to use calculus for this entire assessment. can anyone please tell me how to solve #3, 4, and 5?

please give a few hints. i am really stressed and worried about this and my report is due soon.

please help!

thanks in advance!

[Referos]

Without using calculus, you can do what the assignment tells you and use a spreadsheet and an iterated function to find approximate results. Besides solving the problem, you get more points in the "usage of technology" criterion.

[6Alhinai6]

Hello Everyone

Ok this is my first time using this forum so please forgive me if I have opened this new topic unnecessarily because other topics regarding this ia might have already been posted. I cannot find the other thread to post there so I had to open a new topic because I really need help urgently.

A few days back in my math HL class I got my second IA called: Modelling the Course of a Viral Illness

I have looked at all the questions and even tried half but I need some clarification and help on the following:

For the first part, it says that fever lowers the rate at which viral particles replicate to 160% every four hours. I thought percent increases are always under 100%. I mean even if the viral particles were doubling they would be increasing by 100% every four hours. So where did this 160% come from? Does this sheet assume that when viral particles double, they increase by 200% so the fever basically lowers it to 160% lowering it by 40%?

Secondly, I know this is a common question but I am deeply stuck on #3. I know this question has been asked before several times in other threads and I have gone through those threads many times but I am still confused. I know answers are not allowed and I am not asking for the answers but can anyone guide my though the steps? For #3 I have the equation Y = (YO) 1.6^(t/4) - (1.2 X 10^6)t where Y= number of viral particles in the body at time t, and YO= initial number of viral particles in the body at time t. Is this equation ok? When I differentiated it, as many people in other threads told to use differentiation, I got: dY/dt = (YO) (1/4) 1.6^(-3t/4) - (1.2 X 10^6) Is this ok? If my both original and differential equations are right, then how do I solve for t because right now I have too many unknown variables. Are there any values I am supposed to substitute for t or any other variable?

Lastly I am very confused about the methods needed to solve #4 and #5. My methods seems too easy. I simply decided that the patient will first get injected with a dose of 90 micrograms in the first hour and then for the rest of the 3 hours get injected with 2.5 micrograms of medicine to make up for the 2.5% removed by the kidneys and keep 90 micrograms running. For #5 I simply took the 90 micrograms dose of the first hour, and added (2.5 micrograms) X 3 for the doses of the rest of the three hours to get a total of 98.66 micrograms of dose D given at the beginning of each 4-hour interval to maintain 90 micrograms throughout. Is this the right way or is there any other method?

Please Please help me! My IA is due soon and I would really appreciate your help!

Thanks again everyone! and please excuse my mistakes as this is my first time on this forum! Thanks! Looking forward to your replies!

I'm having problems with question two as well...i get that the viral particles are increasing at a rate of 160% every 4 hours and are being eliminated at a rate of 50000 every hour but it is correct to use compound interest to get the rate per hour and then subtract the rate of elimination per hour....i've been goin around in circles with this question and i've tried to find an equation for it for about a week...the only way it makes sense to me is usin compound interest but i've been getting this idea of using eulers number - e^(..)- but it didn't work out...any help would be really appreciated cuz lookin at question 2 for days has been drivin me crazy...if any one can help thanx =D

[DJ CAS]

Here is a good discussion on this portfolio.

http://www.thestudentroom.co.uk/showthread.php?t=578628

[Austin Glau]

yes! finally done lol

@ 6Alhinai6

As I am sure many others had said, think about differential equations. Continuous Compound interest can also work for this, and so can even converting the base and coeffecient to seconds. However, each method has its own ups and downs, such as reliability, tediousness, accuracy, ect. You are on the right track, and seeing this thread is like a year old you probally got it by now lol

btw, thx DJCAS

Edited March 16, 2010 by 2401 I Hate Tangents

[Austin Glau]

Yeah, I use Anvir Free which is better since it is free, considering the name, and also because It gives you all control over your computer, like an advanced task manager. I think I can handle myself

Also since I don't really see any problems with people having pc trouble in this thread, please don't spontaneous advertise if you can help it. thank you.